C++ Community Plugin mishandles file suffixes

[wenns]

The sonar.cxx.suffixes property doesn't work as documented. The documentation states that suffixes should be specified without a leading period ('.'), but that leads to e.g. file 'binaryh' being parsed as a source file, which ultimately causes a database exception when the contents of the binary file are written to a text database column. The workaround is to specify suffixes as e.g. ".cpp,.h". If that is the desired syntax, the documentation should be updated to reflect that, and the default suffixes list as well (which do not include leading periods either). Otherwise, the code should be changed to prepend the leading period internally.