scans and parses even more Python files

splits parser tests into classic java-based tests and doctest-style tests which are nicely displayed in the IDE's junit test runner

518 (2 tests have bad encoding) successfully scan & parse with this commit

syntax test now generates 520 single test cases and looks so much nicher in my IDE's junit test runner

with this commit, all 149 library files of the Python 3.0 distribution can be scanned and parsed (not necessarily correct) without exceptions

implements correct parsing of a simple statement with a trailing semicolon

eats br'xxx' literals (bytes and raw strings still don't work)

string escapes were and still are not 100% correct (need more test cases)

adds float literals

adds string escape processing to the scanner

adds bin, oct and hex integers (floats still missing)

implements multiple assigment

fixes string scanning which I accidentally broke before

adds hex constants to the scanner

adds line continuations to the scanner