Add several useful MySQL functions
Add several useful MySQL functions

Functions useful for examining and manipulating MySQL databases:
- execute() -- execute one or more MySQL statements (as a single string),
  optionally on a specific database. Returns the same thing as core.system()
- check_execute() -- same as execute(), but checks return code and
  errors out on failure. Returns the same thing as core.check_system()
- dbdump() -- create a dump of one or all mysql databases in the given file

efajardo/osg-test,efajardo/osg-test