matplotlib/matplotlib — pull request #2555 by JanSchulz (2013-10-28 20:32:28+00:00)
Title: Make it possible to add mpl.rcParams to itself or deepcopy

Before it was not possible to set all rcParams to mpl.rcParams or use
copy.deepcopy on mpl.rcParams.

There were two problems:
1. validate_bool_maybe_none(None) was raising ValueError
-> fixed by accepting this value
2. svg.embed_char_paths was deprecated by svg.fonttype but both have
different valid values (bool vs strings).
-> fixed by adding a "value translation" lambda to _deprecated_map
which translates the boolean values to the string values of
svg.fonttype.

Also added a new test for this: mpl.tests.test_rcparams.test_Bug_2543()

I wasn't able to compile matplotlib under my windows environment and only did the changes in my original installed mathplot and the test in a ipyhton notebook. So please check and test before merging...