Documentation dictonary according to #257

I wasn't really sure how to format the dictionary. All informations are inside file as comments.

Things needs to be figured out:
* There is problem with adding default values (they vary somewhere), e.g geom_rect has default 'color': '#333333 and geom_abline 'color': 'black'
* Some of the parameters can be required in some geom but are optional for others. Numpy documentation standard doesn't notice adding bold font to required parameters to higlight them.

I have some time now, so don't hesitate to ask for next help.