Get rid of dependency on boost/operators.
Declare split() function inline.
Remove superfluous try/catch(BufferIsFull).

Buffer is auto-growing, so this exception can never be thrown.
Move OSMObject::operator== and OSMObject::operator<.
Complete item_type <-> char/string conversion and simplify << op.
Turn warnings into errors for check-includes.
Remove superfluous default cases in some switch statements.
Make sure XML parsers returns proper results even when ending prematurely.
Test XML parser without the threading.

The new test code exercises the XML parser without the threading that normally
is used. This makes it easiert to distinguish between genuine XML parser
problems and problems related to threading.
Use renamed test cases and fixed indentation.
Fix typo
More detailed exceptions thrown from XML parser.