This adds a lot more unit tests for Common::INIFile and fixes some small
problems identified during their creation. Specifically:
* addSection() did not check the validity of the section name, which meant it
was possible to create a section that could not then be operated on by the
other functions (which all check validity)
* If allowNonEnglishCharacters was set, it was possible to create a key or
section name starting with '[' or '#', or including a carriage return. This
would not read back in correctly.
* Blank section and key names were considered valid, but neither would be
read back in correctly.
* The struct documentation did not mention whitespcae handling or that comments
include the '#' and carriage return.
Adding @defgroup and @ingroup doxygen tags into all headers
in the common folder that contain doxygen blocks.
This improves the structure, readability, and findability
of information in the resulting output.
This commit targets purely structure and does not deal with
the content of the currently existing doxygen documentation.
