* Factor out PROPERTIES object from the PCB plugin code and move it into
common so it can be used by both the Pcbnew and Eeschema plugins.
* Add schematic I/O plugin manager for loading and saving schematic and
component library files.
* Add initial attempt at a parser for current schematic file format. This
parser will be infinitely more strict than the current parser which is very
forgiving in what it parses.
* Make minor changes to the base bitmap class to support the new parser.
* Add find root sheet support to sheet object to allow fetching the root
sheet from any sheet in the stack.
2. Whole bunch of pointless casts removed
3. Unused variables removed
4. Fix bug caused by JP on April 25, 2015 where strings were adjusted for translation and the hotkeys section table accidentally swapped the footprint editor title with tag, resulting in "footprint editor" being exported instead of "[footprinteditor]"
No functional changes besides #4, technically it'll "break" imports hotkeys files but April 25 broke imports as well.