* changing dependencies from unity->cmock
* added component.mk and Makefile.projbuild
* ignore test dir in gen_esp_err_to_name.py
* added some brief introduction of CMock in IDF
* moved C++ examples to a new cxx folder in
examples
* added experimental C++ component
* added ESPException class to the C++ experimental
component
* added test cases for ESPException and
corresponding test macros