Port git.js to dart APIs.

Exposes git.js APIS as dart APIs.
Don't instantiate git api.
add a test file for the git library
Move git files to git/ folder

Move git.js => git/git.js
Move git.dart => lib/git.dart

Other minor fixes.
Fix git include path in git_test.dart
Extract out zlib module out of git.js

Remove zlib module from git.js. The idea is to move out code module by
module from git.js, and either write dart wrapper, or re-write in dart.
changing the bootstrap script to automatically add .precompiled.js
Include zlib dependency files.

Remove trailling whitespaces in git.js
Move misc_utils module out of git.js

Move misc_utils module out of git.js and make it global.
This module has no dependency. As a next step I will re-write it in
dart which will help to port other code to dart.
added a library name
remove unused parts of spark.html
Build version 0.0.2