ENH: add repeated measures twoway anova function

initial commit
COMSMITS
ENH: add test + fix bug in effect coding
ENH: actually add the file ...
ENH: fix GG adjustment
ENH: add Time-Frequency repeated measures example
COSMITS
ENH: address discussion, improve efficiency
ENH: various enhancements

- improve performance (thanks Eric!)
- improve example
- update test
- add comments to clust_level.py I had been happy about when starting.
COSMITS
Rebase + update what's new
COSMITS II
ENH: add dsPM source space example
FIX: tfr example
ENH: use consistent file names
ENH: various enhancements

- addressed discussion
- imporoved examples
    - added FDR to TFR example
    - added source interaction plot to spatio temporal example
- bug fixes: dofs were computed th wrong way
- refactored the anova function and dropped parallel
- added f_threshold_twoway funciton
- improved tests
ENH: various fixes
ENH: add external test + update names
ENH: add missing test
FIX: last commit