DUI: long names truncation(methods)

Sorry, I just wanted to rename branch from `DUI-LongNamesTruncation(classes)` to `DUI-LongNamesTruncation(methods)`, but it was created another branch, seems I have done something wrong.

Old one PR is [here](https://github.com/Benglin/Dynamo/pull/59).

I have done truncation with using `TextTrimming` property. But I couldn't find solution to cut it with 2 dots. I don't think that EB would be pleased.

# Reviewers
@Benglin,@vmoyseenko, please take a look.

Link to YouTrack:
[MAGN-4376 Long names need to be truncated](http://adsk-oss.myjetbrains.com/youtrack/issue/MAGN-4376)