REF: Refactor arfilter. Correct name and split. Closes #1478.
ENH: Add seasonal_decompose function.
ENH: Use pandas nanmean. Numpy too new.
TST: Old pandas can't assign nan to int series.
REF: Convert to array before checking finiteness.
ENH: Let non-ts pandas objects through. Need to set freq.
ENH: Return pass through function
ENH: Check MS not MS- for freq
ENH: Pull out seasonal_mean function.
ENH: Use convolve to properly handle missing values.
WIP: Start work on pandas io decorators.
REF: Update code for pandas wrapper refactor
ENH: Add pandas wrappers. Test filters.
REF: Move seasonal out of filters.
ENH: Add a results class with a plotting method.
DOC: Add seasonal_decompose to release notes.
REF: Make sure x and filt have same dimensions.
ENH: Only allow 1d inputs to recursive_filter
ENH: Clear up behavior for 2d convolution.
TST: Test 2d convolution filter.