Update install documentation to include FreeBSD

Summary:
Fixes T4024.

  - Mention FreeBSD by name.
  - Make "install this on a normal computer" more explicit.
  - Make "install this on a entire domain" more explicit.

Test Plan:
{F74892}

{F74891}

Reviewers: btrahan, chad

Reviewed By: chad

CC: aran

Maniphest Tasks: T4024

Differential Revision: https://secure.phabricator.com/D7397

src/docs/user/installation_guide.diviner

@@ -6,25 +6,59 @@ running.
 
 = Installation Requirements =
 
-Phabricator is a LAMP application suite, so you basically need LAMP:
+You will need **a computer**. Options include:
 
-  - **Linux**: Some flavor of Linux is required. Mac OS X is an acceptable
-    flavor of Linux. Windows is not an acceptable flavor of Linux. Phabricator
-    will not install or work properly on Windows. (If you want it to, send
-    patches.) Phabricator has active contributors running it on Mac OS X, Amazon
-    Linux, Ubuntu, RHEL and CentOS; if you run into issues on other flavors,
-    send patches or complaints.
-  - **Apache** (or nginx, or lighttpd): You need Apache 2.2.7+ (or another
-    tested webserver). You can probably use something else, but you're
-    on your own.
-  - **MySQL**: You need MySQL.
-  - **PHP**: You need PHP 5.2 or newer.
+  - **A Normal Computer**: This is strongly recommended. Many installs use a VM
+    in EC2. Phabricator installs properly and works well on a normal computer.
+  - **A Shared Host**: This may work, but is not recommended. Many shared
+    hosting environments have restrictions which prevent some of Phabricator's
+    features from working. Consider using a normal computer instead.
+  - **A SAN Appliance, Network Router, Gaming Console, Raspberry Pi, etc.**:
+    Although you may be able to install Phabricator on specialized hardware, it
+    is unlikely to work well and will be difficult for us to support. Strongly
+    consider using a normal computer instead.
+  - **A Toaster, Car, Firearm, Thermostat, etc.**: Yes, many modern devices now
+    have embedded computing capability. We live in interesting times. However,
+    you should not install Phabricator on these devices. Instead, install it on
+    a normal computer.
+
+You will need an **operating system** which is **not Windows**. Phabricator runs
+on most operating systems which are not Windows.
+
+  - **Linux**: Most installs use Linux.
+  - **Mac OS X**: Mac OS X is an acceptable flavor of Linux.
+  - **FreeBSD**: While FreeBSD is certainly not a flavor of Linux, it is a fine
+    operating system possessed of many desirable qualities, and Phabricator will
+    install and run properly on FreeBSD.
+  - **Solaris, etc.**: Other systems which look like Linux and quack like Linux
+    will generally work fine, although we may suffer a reduced ability to
+    support and resolve issues on unusual operating systems.
 
 NOTE: The command line interface to Phabricator, "Arcanist", //does// work on
 Windows. For instructions, see @{article:Arcanist User Guide: Windows}.
 
-You'll probably also need a **domain name** and you'll certainly need
-**a computer** with a connection to **the internet**.
+Beyond an operating system, you will need **a webserver**.
+
+  - **Apache**: Many installs use Apache + `mod_php`.
+  - **nginx**: Many installs use nginx + `php-fpm`.
+  - **lighttpd**: `lighttpd` is less popular than Apache or nginx, but it
+    works fine.
+  - **Other**: Other webservers which can run PHP are also likely to work fine,
+    although these installation instructions will not cover how to set them up.
+  - **PHP Builtin Server**: You can use the builtin PHP webserver for
+    development or testing, although it should not be used in production.
+
+You will also need:
+
+  - **MySQL**: You need MySQL.
+  - **PHP**: You need PHP 5.2 or newer.
+
+You'll probably also need a **domain name**. In particular, you should read this
+note:
+
+NOTE: Phabricator must be installed on an entire domain. You can not install it
+to a path on an existing domain, like `example.com/phabricator/`. Instead,
+install it to an entire domain or subdomain, like `phabricator.example.com`.
 
 = Installing Required Components =
 

src/docs/user/userguide/arcanist.diviner

@@ -77,9 +77,14 @@ SVN repositories.
 = Installing Arcanist =
 
 Arcanist is meant to be installed on your local machine or development server --
-whatever machine you're editing code on. It runs on Linux,
-Mac OS X (see @{article:Arcanist User Guide: Mac OS X}), and
-Windows (see @{article:Arcanist User Guide: Windows}).
+whatever machine you're editing code on. It runs on:
+
+  - Linux;
+  - Other operating systems which are pretty similar to Linux, or which
+    Linux is pretty similar to;
+  - FreeBSD, a fine operating system held in great esteem by many;
+  - Mac OS X (see @{article:Arcanist User Guide: Mac OS X}); and
+  - Windows (see @{article:Arcanist User Guide: Windows}).
 
 Arcanist is written in PHP, so you need to install the PHP CLI first if you
 don't already have it. Arcanist should run on PHP 5.2 and newer. If you don't