Training Tools

This branch contains 3 training tools:
Speed report: a typing speed indicator
Predictions: Similar to the StenoTray tool, that provides a list of endings for what you have already typed
Brief Trainer: Searches the dictionary for what you have just typed, to suggest shorter briefs.

Each of these is available from the configuration menu, under the last tab which was renamed from Display to Training.

Predictions and Brief Trainer utilize a 2nd copy of the dictionary (reverse lookup) stored in a ternary search trie, and can take noticeable time to load on slower systems.  

(note: I removed the "space before" commit that I didn't intend to include here)