Add support for the scroll wheel to the video slider
Also forward page up/down and home/end from the video slider to the subs grid
Use ForwardMouseWheelEvent rather than checking window bounds
Eliminate a bogus limit of 100 for a bunch of rarely-used options
Build parser.cpp first

Shaves a few seconds off parallel builds with 4+ cores by avoiding
having everything else finish while it's still building.
"Allow grid to take focus" -> "Focus grid on click"

The grid can still be focused via the keyboard, so the previous label
was misleading.
Update to latest wxWidgets
wxStandardPaths is protected as of wxgtk 2.9.5

Closes #1625, #1626, #1627.