Now compatible with python2.6

Also tested with matplotlib < 143 test203 fail
because in that version the function set_xlim was not
yet existing.

All version of matplotlib < 143 are not considered as stable
therefore not supported.

I add a message in __init__

I also corrected a bug I added in a former commit:
  I prevent myplotlib.__init__ from importing tests
  but just testList.

This prevented `python myplotlib --test <test name>` to work
because no tests were in myplotlib.__dict__

So I change the import from:
from . import __dict__
to
from .test import __dict__

Now `python myplotlib --test <test name>` works