Minor clean up of string format specifiers
	modified:   Source/OCMock/OCMockObject.m
	modified:   Source/OCMock/OCObserverMockObject.m
Clean up of test string format specifiers and redundant use of 'stringWithString
' method with a literal
	modified:   Source/OCMockTests/NSInvocationOCMAdditionsTests.m
	modified:   Source/OCMockTests/OCMockObjectTests.m
Merge pull request #23 from subsymbolic/master

Minor corrections to clear build warnings