fix warnings due to -Wunused-parameter
fix warnings due to -Wunused-variable
fix warnings due to -Wswitch
fix warnings due to -Wparentheses
fix warnings due to -Wunused-function
fix warning reg. "name xxx already in use"

using the names they defaults to
fix error introduced when fixing warnings due to -Wswitch
fix error introduced when fixing warning -Wunused-function
fix cmake warning with cmake >= 2.8.11
fix warnings due to -Wunused-but-set-variable
Merge pull request #656 from Jojo-Schmitz/warnings

Fix warnings under Windows and with Qt-Creator