[examples] e231 fixes

Signed-off-by: Thomas Hisch <t.hisch@gmail.com>
[examples] fix e241 where it makes sense

Signed-off-by: Thomas Hisch <t.hisch@gmail.com>
MNT : removed *args from CallbackRegistry init

Specified to be removed for 1.5
simple typo in whats_new
RST issue in legend doc
Merge pull request #3767 from jenshnielsen/doc_fixes

RST fixes for the docs
Mock wx and wxversion

     When building the docs.
Mock PyQT4 when building docs
Cleanup import and remove unused patch
Merge pull request #3764 from tacaswell/cb_args_deprecate

MNT : removed *args from CallbackRegistry init
Merge pull request #3714 from thisch/pep8fix_e231_e241

[examples] fix pep8 error classes e231 and e241
Merge pull request #3768 from jenshnielsen/mock_backend

DOC : Mock backends when building docs