Test fixes

This fixes three tests in gccxml:

1. The first run of unit tests would fail if the build dir didn't exist, now we ensure it does
2. The Point class was not registered in the typesystem.
3. Default newlines are represented in gccxml by their octal character code, now we eval these strings.

This also increases stability by ensures the parsers get there own build dirs and that these build dirs are cleaned before running the unit tests.