Avoid storing issues multiple times

Reduces the number of issues dramatically
Faster analysis of a project
Better user experience while viewing issues
Avoid NPE and enhanced file name management
Report number of Vera++ issues for logging
Improve rule names for compiler sensor
Enhance and correct PC-lint test files
Incorporate comments
Handle exception for invalid XML char in PC-lint report

- after PC-lint crashed (C++11 issue)
Move getCaseSensitiveFileName() to compiler sensor and write only one warning per unresolvable file path
Merge pull request #100 from Bertk/sensor-improvements

PCLint / compiler sensor improvements