Fixed all unit tests.
Removed constant padding added around tables in the last step of the
initial discovery mode of the stream algorithm.
Replaced it with a heuristic that attempts to expand the table up while
respecting columns identified so far.
Updated unit tests to reflect new behavior, improved rejection of
extraneous information in few cases.
Added unit test covering a use case where the header has vertical test.
Made improvements to better support vertical text in tables.
* Rename png files
* Convert plot to PlotMethods class and update docs
* Update test
* Update setup.py and docs
* Refactor PlotMethods
* Make matplotlib optional
* Raise ImportError in cli
Francois Huet
Vinayak Mehta