added cli / changed structure

Hey @addyosmani,
i've got some changes for you ;)
* Added CLI #3 (hope it's minimal enough)
* Allow plain `html` as source for `generate`and `generateInline`
* Use `tmp` for tmpfile handling (should also be a better fix for #44)
* Cleaned the filesystem structure a bit (tests in `./test`, source files in `./.src` and bin in `./bin`)

Thought there were to much changes to just push it into master ;)