Pcbnew: minor target properties dialog improvements.

* Make spacing between controls and dialog frame consistent.
* Use default size to allow wxWigdets to determine optimal dialog size.
* Set OK button as default so return key works properly.
FIX: regression loading of SMD pads within EAGLE_PLUGIN::FootprintLoad().
FIX: unique renaming of eagle footprints by substituting illegal : and / with URL encoding technique.
ADD: window resize border to DisplayError() windows.
Add template fp-lib-table for eagle-6.4.0
Pcbnew: Code cleaning and some minor fixes.