Added info directory.
Classified tgi_imulround() as part of TGI API.
Added cc65_umul8x8r16() based on umul8x8r16.
Finetuned Git commit hash retrieval.

- Force usage of shell wrapper in order to allow to suppress potential message about git not found (thanks to Greg King).
- Do $(info GIT_SHA ...) only if there's something special - as done with the other $(info ...).
Fixed typo.
Added explicit wiki link.
Merge pull request #99 from groessler/something_to_pull

Make ld65 command line arguments position independent.
Fix error which slipped in in '-L' command line parameter handling.