Merged in bitwise-expression branch from svn.

This is still a highly experimental branch.
Updated qm.py from the online repository.
Merge branch 'master' into bitwise-expression
Cosmetic changes: renamed some functions.
Merge branch 'master' into bitwise-expression

Conflicts:
	crc_opt.py
	doc/pycrc.xml
Deleted espression parser
Standardised the algorithm shorthands to TLAs.

Renamed bbbf to bbf and td to tbl.
Merge branch 'master' into bitwise-expression

Conflicts:
	crc_opt.py
	doc/pycrc.xml
Improved error reporting in the code generator.
Merge branch 'master' into bitwise-expression

Conflicts:
	doc/pycrc.xml
Removed the qmtest.py script.