tentative std::mutex locking

Conflicts:
	samples/cppTest/Project.xcconfig
	samples/cppTest/cppTest.xcodeproj/project.pbxproj
Added makefile with -D USE_STD_MUTEX compiler flag for cppTest
Renamed USE_STD_MUTEX preprocessor define to LIBPD_USE_STD_MUTEX
Added -DLIBPD_USE_STD_MUTEX and -std=c++11 to xcode project
Made a cpplib target in makefile
Deleted xccheckout file
Merge branch 'cpp-queued' of https://github.com/rvega/libpd into cpp-queued

Conflicts:
	samples/cppTest/cppTest.xcodeproj/project.xcworkspace/xcshareddata/cppTest.xccheckout
Merge pull request #69 from rvega/cpp-queued

Merging locks from cpp-mutex branch into cpp-queued branch.