pcbnew: added 5 metric grids and fixed a very minor bug when creating drill map.

globbing handler. There should be no reason the mask cannot have two '*'s
in it.

The wildcard part of the mask component should be discarded when the user
picks an actual file. For now, we work around this bug by removing the
2nd mask.

minor changes in search paths for help and translation files.

Mandatory in Pcbnew to handle without error metric grid used now for some footprints (BGA, connectors)
Not fully tested

Comments added in some functions.

Integrate wxFileHistory, add missing header files to fix Linux build, initial search path work, and general housekeeping.