cppsp: fixed bug where page would be stuck in the "compiling" state if compilePage() throws an exception or returns NULL
delegate.H: fixed compilation error (added explicit cast)
cpoll: String: allow setting a String to nullptr or NULL
cppsp: change http status to 500 when errors are encountered
cppsp: insert "#line" statements to generated c++ to make line numbers correct in the "compilation error" display
cppsp: keep a copy of generated c++ file in case of compilation error
cppsp: don't attempt to parse/compile if file does not exist
cppsp: stringutils: added ability to urlDecode() directly to a StringPool
cppsp: eliminated one malloc and one copy during querystring parsing
cppsp_standalone: remove unnecessary #define