Improve API Config generation.

Fixes #4 (Conform to enconding/json.Unmarshal struct field's tag rules)
Adds support for required, default, min, max and description param options.
Describe what's happening during package install (go get) in details.

Closes #9 (Can't go get github.com/crhym3/go-endpoints/endpoints)
Moving sample apps to their own repos

tictactoe app: https://github.com/crhym3/go-tictactoe
go-endpoints.appspot.com: https://github.com/crhym3/go-endpoints.appspot.com

Closes #8
Merge branch 'master' of github.com:crhym3/go-endpoints