Fix the formatting at "Initialize submodules".

Only seems to be missing in some cases but can’t hurt if already
installed.

Also added Qt version check.
And made the platform/toolchain check a little more descriptive.

Now all prerequisite packages should be listed for Arch, Fedora, and Ubuntu.

Updated some URLs, docs, and packages. Ubuntu and Arch instructions have not been verified on a live install, but the names come from their online package listings, so they should be correct.

Settings in user_config.pri are overridden by those specified at the command line when calling qmake.
Also updated the README and user_config.pri.dist to be a little more clear about specifying these other options.

Manual override through DISABLE_SPEECH now works on all platforms.

It can now be manually disabled.

Can now be disabled by the DISABLE_KINECT define.
Also better output for users when running qmake.

Added documentation and clarified messages to the user.

This feature can be enabled at compile-time and documentation has been added to the README.

Reduced it to folder descriptions and important files.

Separated into logical steps.
Made optional and required steps explicit.
Added instructions for Fedora.

XBee support can now be disabled by defining DISABLE_XBEE.
Details on why XBee support is disabled are now output.