tracker-extract: Fixed the jpeg extractor to use TrackerSparqlBuilder
tracker-extract: Fixed the jpeg extractor to use TrackerSparqlBuilder

Fixed some other issues while here:
- Don't leak filename if size of file is < 18 bytes
- Use proper types not strings for everything sent using SPARQL
- Fixed some whitespace issues
- Cleaned up the code in places

outofbits/tracker,outofbits/tracker,hoheinzollern/tracker,outofbits/tracker,hoheinzollern/tracker,outofbits/tracker,outofbits/tracker,hoheinzollern/tracker,hoheinzollern/tracker,hoheinzollern/tracker,outofbits/tracker,hoheinzollern/tracker,outofbits/tracker,hoheinzollern/tracker