refs #1433: made functions of ModelicaInternal thread-safe by
 * moving static buffer to localbuf
 * adding thread-local storage for cached_fileName, cached_fp and cached_line

git-svn-id: https://svn.modelica.org/projects/Modelica/trunk@7645 7ce873d0-865f-4ce7-a662-4bb36ea78beb