Squashed 'pothos-blocks/filter/fir_filter/' content from commit b732ed2

git-subtree-dir: pothos-blocks/filter/fir_filter
git-subtree-split: b732ed23fcbd6edc659236db3b6d5b0c704cd7ea
Merge commit '546a1942b455ab02854cc1120c950855fa0f9fae' as 'pothos-blocks/filter/fir_filter'
pothos-blocks: work on FIR designer block
Merge branch 'master' into fir_utils
pothos-blocks: added complex FIR taps, band rejects
fir_filter: fix segf on delete after error - missing pointer initialization
pothos-blocks: cleanup FIRDesigner exception msg
pothos-blocks: cleanup fir_filter for MSVC c++11
pothos-widgets: added parameterized kaiser window
pothos-util: added WindowFunction to util module
pothos-blocks: use new window function from util
pothos-widgets: switch plotters to new window function
pothos: added window documentation comments
Merge branch 'fir_utils'