Fix issues with non-integer positions being sent to the server.

Missed drag and drop. Ooops.
Add new FlowMultiplier element for message duplication.

New element simply copies elements a configurable number of times.
Useful for load testing. Does NOT generate new UIDs for the elements.

Small cleanups.
Fix frequency counter grow behavior.
Change tokenizer to work with a whole list of characters to split by.
Add stopword filter node and switch default list encoding to UTF-8

Also added a stopword list with words from a few languages
as well as some special "words that showed up high on the
frequency counter but are useless (e.g. RT on twitter)