Fix crash when initializing the library from multiple threads
Fix crash when initializing the library from multiple threads

Call xmlInitParser() before setting libxml2 global variables as these
"variables" actually are function calls using global state protected by a
critical section that must be initialized by xmlInitParser() before being
used.

This fixes a crash due to trying to enter an uninitialized critical section
under MSW.

vslavik/xmlwrapp,vslavik/xmlwrapp,vadz/xmlwrapp,vadz/xmlwrapp,vadz/xmlwrapp,vslavik/xmlwrapp