trie generation provides no user feedback

[sfriesel]

Generating a trie can take a very long time, depending on the size of the training file and the cutoff threshold. It would be nice to have some kind of progress indicator to show.

[sfriesel]

Percentage progress is difficult, b/c small parts (e.g. heavily used syllables) of the alphabet space make up the biggest part of processing time. Proposed solution: Show a flattened truncated version of the current trie. For example when currently scanning for the prefix "ismus" the output would be:
abcdefghijklmnopqrs [us] [mus] [smus] [ismus] stuvwxyz :-)!.