Make ld65 command line arguments position independent.
Make ld65 -L command line option position dependent again.
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.
Make ld65 -L command line option position independent again.
Handle long versions of command line arguments correctly.
Merge pull request #99 from groessler/something_to_pull

Make ld65 command line arguments position independent.
Added document lines that name the default device drivers.

Also:
- Changed some <htmlurl> tags to <url>.  Now, those links will show their URL addresses (in addition to their names) in info and text pages.
- Added some Atmos-specific function names to its document.
- Fixed some punctuation syntax.
Fix error which slipped in in '-L' command line parameter handling.
Merge pull request #101 from groessler/something_to_pull

Fix error which slipped in in '-L' command line parameter handling.
Merge pull request #100 from greg-king5/default-drivers

Added document lines that name the default device drivers.
Added doc install target.
Harmonized usage of "KB" and "cc65".