Sorry Max

Setup new os and didn't push, but sasved on a harddrive

Still pretty bad graphs

This is a better approach to analyze the vocabulary growth.

Now the average term length of words gets calculated correctly when
removing special characters.

All words are now saved lowered in cleaned lyrics, all commas get
removed and a new graph is created which represents the ratio of terms
used once in comparison to all used terms.

This commit also implements a test for cleaning/saving all lyrics.

With the new functionality we can track when a word became important,
because we can track when and how often a given term occurs.

The seconds graph for the average term length shall represent the
difference of the average term length with and without the removal of
special characters and constructs like: comin'

Sometimes some single letters were counted in the creation of the
lexical richness, with a min term length of 2 we can rid of those.

now we are able to store and read the lexical richness data of every
year