api doc generator

This is an early draft of the api doc generator implementation.

TODO:

- [x] finsh the model layer to hold all information we need.
- [x] add all information to the offline template
- [x] add command runner bin file
- [x] make templates exchangeable
- [x] markdown support
- [x] resolve links with non fqNames (for doc types this is already done by phpDocumentor :-) )
- [x] resolve class internal links
- [x] complete support for Objects property feature
- [x] polish and cleanup
- [x] display arrays in short syntax
- [x] README file

fixes #62 

depends on phpDocumentor/Reflection#16 to be merged.