Move NULL-check (fixes #8)
Fix MSVC warnings
Merge pull request #10 from tbeu/fix-warnings

Fix MSVC warnings
Fix const qualifier of character array return value

According to MLS 12.9.2 (Return Type Mapping) Modelica ```String``` should be mapped to ```const char*```
Merge pull request #11 from tbeu/fix-const-qualifier

Fix const qualifier of character array return value