changed makefile, added header files for Temperature-, Length- and WeightConverter
forgot to run 'git add .' first...
added interfaces and implemented empty classes
adjusted tinytest.h to actually work with floats (TINYTEST_APPROX) and to PRINT THE VALUES if an error occured...
implemented tests
implemented tests
implemented tests for toString
implemented all convertes, all tests are ok, hurray
added #include <cstring> to ensure compatibility with GNU-GCC (strcmp not found error!).