[3d reconstruction] Add method to re-set calibration matrices

Useful for auto-calibrating systems, for instance.
Prevent a crash when passing no configuration file
Added documentation to build Chilitags for android
Merge pull request #9 from qbonnard/tests

Adding automated tests
Added missing 'include_directory' to compile tests
[3d reconstruction] Accessors to nb tracked objects/markers
CMakeLists: TEST_DATA is a path
Added more stills to unit-tests + new layout in testdata