Created module for Pololu gpio based line sensors

- For Pololu QTR-8RC
- Integrated with RASLib
- Fully tested and working
- Timing values somewhat arbitrary, gives about 1.5 inches of range
Made linesensor.h polymorphic
Changed RASDemo to reflect new RASLib
completed function pointer idea
hidden to _, and created binary
Merge pull request #30 from ut-ras/fls_oop_suggestion

Fls oop suggestion