UNO services for SAX parsing and C++ functions for XMLSchema-2 data types.

* source/expwrap:
    string-based SAX parser UNO service wrapping expat
* source/fastparser:
    multi-threaded token-based SAX parser UNO service wrapping libxml2
* source/tools:
    + C++ wrapper for fast SAX parser
    + C++ XMLSchema-2 data type conversion helpers

Multi-threading in FastParser can be disabled for debugging purposes with:
SAX_DISABLE_THREADS=1 SAL_LOG="+INFO.sax.fastparser+WARN"