Added the added file to CMakeLists.txt
Refactored CheckUsingDirective(...) to not use regex
XML tag key text: RelativePathInInclude
XML tag value: (0 or false to not forbid relative path up access; anything else to forbid them.), it's on by default
Error type: RELATIVE_PATH_IN_INCLUDE
Error tag: RPI
New function: CheckRelativePathInInclude

Tests:
Except for the second test, kwsRunKWStyleTest, all tests are passing. kwsRunKWStyleTest is failing without my changes which indicates an unrelated problem (visual studio 2012 on windows).

Note:
This branch is based off the one in pull request #8, so it includes 2 features.
Pull request #7 needs to be applied for the line numbers to be calculated correctly or use the LineLength rule before this one in the xml file.
Updated CMakeLists.txt to add the two new files