CLN: 0.14 NDFrame cleaning

[jreback]

post #4324

• Fillna column wise, column-wise fillna with Series/dict NotImplemented #4514
• interpolation, consolidate Series/DataFrame interpolation to internals.Block.interpolatte, ENH: Richer options for interpolate and resample #4434, cc @TomAugspurger
• update, CLN: move update to BlockManager method (and just call from frame) #3025
• shift, [BUG] NumPy timedelta64 order of magnitude not changed during date operations #4865, Axis slicer #4994
• sort, API: unify sort API #5190
• dropna API for Series, see FIX: OLS.predict() - cast input to DataFrame from Series before performing operations #5234, ENH: Unify API for drop and dropna for NDFrame #5250
• in place dropna , inplace dropna? #1960

[TomAugspurger]

axis arguments that don't allow for Panel index names:

• drop - BUG/ENH: Allow drop to accept axis name #5354