Fixed cppcheck unusedFunction option

According to the cppcheck manual (http://cppcheck.sourceforge.net/manual.pdf), the correct name of the check is 'unusedFunction' (singular) instead of 'unusedFunctions'.
added support for wdk8 in WinHID
Merge pull request #16 from lpberg/winhid-wdk8

added support for wdk8 in WinHID
Merge pull request #15 from freitass/patch-1

Fixed cppcheck unusedFunction option
Find DirectX XInput library
Improve windows SDK finding.
Fix up OpenHaptics nested targets.
Add FindInterSense.cmake
Update help files.
Fix syntax error in BoostTestTargets.cmake
make GetGitRevisionDescription.cmake aware of submodules
Merge pull request #18 from PiQuer/master

make GetGitRevisionDescription.cmake aware of submodules
that have a .git file instead of a .git directory.
Merge pull request #17 from gunnarbeutner/patch-1

Fix syntax error in BoostTestTargets.cmake
use CMAKE_CURRENT_LISTDIR instead of CMAKE_SOURCE_DIR as GIT_PARENT
This guarantees that the search begins in the subdirectory (submodule)
where the function is called. Otherwise we will most likely pick up
the super-repository.
Merge pull request #19 from PiQuer/master

use CMAKE_CURRENT_LISTDIR instead of CMAKE_SOURCE_DIR as GIT_PARENT
Update backported module and add backported ParseArguments.
Impending CMake 3.0 implies that 2.9.0 is no longer ~= infinity.
Windows SDK updates from working on VRPN
Use CMAKE_CURRENT_SOURCE_DIR in GetGitRevisionDescription.

CMAKE_CURRENT_LIST_DIR is newer, and in this context, it would
almost certainly be identical.
Merging upstream