Refactor browser builder to support API JSON files.

Also support specifying fuzzy versions from services input, like:

s3=latest,dynamodb=2012-01-01

Which will use the latest version for S3 and the latest version at
2012-01-01 of DynamoDB.
Upgrade browserify to 3.x

Helps to improve memory performance issue reported in #207.
Finish implementing new server architecture
Add cache check to server initialization. Allow it to run with cache off
Use app.set/get to access settings, not local vars. Allows tests to mock values
Support cacheRoot
Update server to use async.js parallelization
Update package.json and .gitignore
Rework builder to work without lib path, if cache exists
Use window.AWS in tests again
Update server tests and ensure server returns 400 for invalid modules
Use CACHE_ROOT to specify cache root from command line
No dependency on XML libs
Move init to setup-versions script and change server to serve cache from server-cache/
Look for aws-sdk in node_modules if present
Add cache
Add .gitignore
Search for SDK in parent directory before looking for node module
Depend on SDK for building