NF: yerr can have multiple levels

RF: func -> aggfunc to match pandas syntax
BF: beanplot works

ENH: labeling of axes and legends improved
Merge branch 'beanfix'

* beanfix:
  BF: beanplot works
  NF: yerr can have multiple levels
Merge branch 'master' of github.com:qbilius/psychopy_ext

* 'master' of github.com:qbilius/psychopy_ext:
  ENH: unstacking can be requested for no yerr agg
  BF: eval reanabled in ui so that nums were nums

Conflicts:
	psychopy_ext/stats.py
BF: subplots work now