- Move away from URL to parametric options for mapistore named
properties backend.
- Add unix socket support and different port support to mysql backend
- Encapsulate mysql parameters into a a data structure
- Improve MySQL backend initialization logic and rely on mysqld error
  codes
- Document new smb.conf parametric options in smb.conf
- Remove dead code
- Add sanity checks to modified functions
- Add doxygen comments to functions reviewed