initial commit
using browserify to make app script. QueryBuilder at unwind stage currently.
functional pipeline building. needs testing.
moved example to index.html (more natural there).
added support for multi-key grouping.

the output is a nested object for the group key. is that what we want?
added example.
Merge branch 'master' of github.com:rueckstiess/mongodb-querybuilder

Conflicts:
	LICENSE
	README.md
still working on .pick().