Initial commit of build task
Adding support for the Closure Builder.
The following tasks are added to the project:
getClosure : Uses git to download a copy of the closure library to the
specified location.  If the location exists, this task is skipped

buildJs : Uses the Closure Builder python script to order and combine
all dependencies for the specified namespace

depsJs : Use depswriter.py to write out the locations of the project
files for use with goog.require

The Closure tutorial's notepad.js is added as an example with
notepad.gradle showing how to configure it