Merge pull request #204 from ddobrev/master

Ignored protected members of value types. Used a constant for the instance identifier to improve performance
Merge pull request #205 from ddobrev/master

Marshalled C++ char as Mono/.NET char instead of sbyte for a more friendly API
Added support for default values of parameters. Fixed the reporting of compilation errors.

Signed-off-by: Dimitar Dobrev <dpldobrev@yahoo.com>