Fixed Doxygit.cmake, removed doxygit target from DoxygenRule, added CommonDocumentation.cmake.
Merge pull request #219 from rdumusc/doxygit_v2

Fixed Doxygit.cmake for 'make doxygit', added CommonDocumentation.cmake.
Add dummy install target for common_documentation, as expected by Buildyard.
Merge pull request #220 from rdumusc/installtarget

Add dummy install target for common_documentation, as expected by Buildyard.
Package found variable is internal to the dependent project
Merge pull request #221 from bilgili/master

Package found variable is internal to the dependent project