NEEDED for public beta release
* hook up feed override
* fill out menu bar
* make step button work / state of step button
* make status bar reflect reality (only machine state so far) 
* make active g-codes work (or ungrid it for now)
* A NAME
* set first line

NEEDED for 1.0
* use real rs274 parser instead of homebrew
* integrate build of Togl
* install pyemc in emc's plat bin directory

BUGS
* click a line, then load a file.  the old line stays highlighted
* initial state of play button is wrong (depressed)

Wishlist items
* improve opengl navigation
* Way to show diameter of drills, width of cuts (poor-man's CSG preview)
* Way to turn off lines already plotted in live preview
* context menu on code area, options "copy", "start at this line"
* make the view follow the cone around

Missing dialogs/subwindows from xemc:
* tool list editor (at least display?)
* axis editor
* informational dialogs like xemc
