Fixed bugs in KiwiFrameBuilder

- in computeKiwiFrameChecksum, kiwiFrameChecksum was not initialized,
potentially causing trouble
- in buildKiwiFrame, all analog sensors values were written in field 1
- in buildKiwiFrame, last of 8 sensors was not written in frame
Removed useless declaration in Logger.cpp

- filePath was declared twice (in .h and in .cpp)
Syntactic change in CustomFrameBuilder