Install

TextMate Version 2.0 Alpha

mkdir -p ~/Library/Application\ Support/Avian/Bundles
cd !$
git clone git://github.com/b00y0h/Bobby.tmbundle.git

TextMate Version 1.x

cd ~/"Library/Application Support/TextMate/Bundles/"
git clone git://github.com/b00y0h/Bobby.tmbundle.git
osascript -e 'tell app "TextMate" to reload bundles'

Set Project-wide variable

The way to do this is currently a little secret but if you deselect everything in the project drawer, then click the info (circled I) button, a panel will appear where you can set variables.

Create a variable called MY_LOCALIZE and set it to whatever you need.

(Original instructions stolen from the GitHub Bundle.)