Merge fixes added to master into experimental

Modified wildcard for FileDialog to add an choice to show All Files

preview zoom by key

zoom big preview by shift + key

Minor fixes

Made lines starting with $ pass through

Made greetings configurable (no longer just 'start')

Fix some translation strings and update translations

Handle exceptions raised when printer is disconnected 

OS X pre-lion comes with readline preinstalled in the system python.

changed console window log hiding pattern logic to avoid memory leaking and newlines separating from lines to be hidden

Italian translation

Handle g0 equal to g1.

Threaded gl rendering

Green is feedrate now

gcode viewer, for now in separate file