Basic Mallet library implementation

Mallet library integrated into project, basically functioning with bugs.

Currently, must run ImportData.java to generate processed output, then
TopicModel.java to develop topics from output. Should have the classes
call eachother or develop a central Main class to handle running them
both.

A number of current issues with ImportData.java; not sure how to fix.
Many data pieces have (seemingly) random letters added to the start and
end. Commonly 't'. No idea where this has come from.

Also the processed output generated by ImportData.java includes
file-paths and library names from the source. No idea how to fix this at
the moment.