Add key presses as sensors

[GoogleCodeExporter]

Had a couple requests that people would like to treat keys like sensors (when a 
key is pressed, do this). Might be fun and it would also allow integration with 
MaKey-MaKey. Seems like a good thing to add during a summer internship.

Original issue reported on code.google.com by tlauw...@gmail.com on 10 Mar 2015 at 2:38

[jenncross]

This can be treated (similar to Scratch):

• Sensor Type: Drop Down "Keyboard"
• Select Keyboard: Drop Down "A B C D E F......, space, up arrow, etc" (most reasonable keyboard options)
• The two sensor tracks/states can be labelled "Pressed"/"Not Pressed" or something like that