linux port, eclipse project + testapp

Here's the library port to Linux + gcc. I was unable to port tests yet, but app now works fine. There were some crashes when photo doesn't have geo information, so I had to put some parsing into try/catch block.
We need to change somehow Location interface to reflect that lat & lon are actually optional. As a temporary solution you can call getOptionalSubvalue instead of getValue for lat & lon and fill it with 0 if it's not present.