Fix for MySQL version check subroutine (issue #7)

Adopting scop's idea for more reliable version recognition, both for local and remote servers.

Version check should work as follows:
- assuming that 32-bit version of MySQL is used by default
- check if 'version_compile_machine' ends with string '64' - if yes, then change version to 64-bit (on non-Windows OS)
- check if 'version_compile_os' ends with string '64' - if yes, then change version to 64-bit (on Windows OS)
- in all other cases MySQL version should be 32-bit