Added missing function_traits file and its entry in cmake
More html_page functions
        added proxy methods for xmlrenderer::render::create_X
        created response-type selection functions and variables

Added missing add_test in cmakelists
Moved html_page test boot to header, to simplify future html_page tests.
Created controller_t, base class for all request handlers:
        flush() abstract function is used for rendering XML/other output to response,
                it is now at 6th position in request lifecycle (see tests/webpp.cpp)
Fixed bug in query_matcher: indexed_values were in incorrect order (ordered by name, not insertion order)