TextMate - Search in Project With ack

I've moved the Search in Project With ack TextMate command to GitHub.

In the process I've included a change by Corey Jewett to respect the selected files in the project drawer, and I've also added support for the TM_ACK_COMMAND_PATH variable, in case your ack copy is somewhere strange.

There is an open TODO (catch popen errors if the ack command is not found), but I need to freshen up my ruby skill. It should be trivial, push requests welcome.

This is a very simple command. If you are looking for something more complete check out the ack TextMate bundle by Trevor Squires.