Adds Android SDK and Android Platform Tools.

Adds Android SDK and Ant to Brewfile. Exports ANT_HOME, ANDROID_HOME,
ANDROID_PLATFORM_TOOLS shell variables and adds these to PATH variable.
Adds brew linkapps command to Python Brewfile.

Homebrew now symlinks .app bundles for IDLE, Python Launcher, et cetera
into /Applications
Adds a merge config for Rails schema conflicts.

Rails schema version conflicts will always be resolved using the newer
schema version. Since it is unlikey other projects will have a schema.rb
file where this rule would cause a problem, it has been added globally
rather than using a Rails specific gitattribute files per project.