Fix .gitignore and minor changes

Hello Phil,

this pull request includes the following minor changes:
- fix ```.gitignore```
- remove *.obj files in ```csrc/```
- fix compile scripts (skip copying binaries, will be done by ant)
- include ```<OpenCL/cl.h>``` in ```OpenCLRuntime.c``` for Macs
- add ```toString``` in ```RootbeerAtomicInt.java```

Martin