* 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
The following commit updates the first half of the the system
example README files. Some other changes were also made:
* Updated base_mac_address example
* Moved contents in GCOV README to GCOV docs
* Some *main.c file names updated
* Updated example README template
