Make includes consistent: Google C++ style guide, no "../", etc.
cppcheck: update include folder.
clangformat on OTSignature.hpp.
Merge pull request #293 from benma/cleanup

Made all includes consistent
OTMessage: remove nReturnVal, return at the end of the block
process attribute success in separate method
refactor OTContract::LoadEncodedTextFieldByName
do not use shared pElementExpected in OTMessage::ProcessXMLNode
do not use shared strDepth in OTMessage::ProcessXMLNode