Add dropEmptyRows and dropEmptyCols [510](#510) Fix ambiguous sum fun…

…ction when calling it from Frame [515](#515)

Add linear regression and PCA functions in Deedle.Math thanks to @Ild…

…hesten [496](#496) Add descriptions to Stats functions to clarify valid input types by @Arlofin [501](#501)

Fix parsing csv of multi-line column headers [#479](#479) Fix type in…

…ference of empty cell [#441](#441)

Fix FilterRowsBy [#491](#491) Add basic stats functions of Frame in e…

…xtension [#490](#490)

Release Deedle.Math to extend linear algebra, statisitical analysis a…

…nd financial analysis on Frame and Series by leveraging MathNet.Numerics [#475](#475) Override + operator and add Frame.strConcat to concatenate Frame and Series of string values [#482](#482) Fix ResampleUniform with missing values [#470](#480)

Fix RowsDense broken by BigDeedle changes (#319) Make ChunkSizeInto b…

…ehave according to documentation (#314) Expand public fields (#313) Keep order of columns/rows in FrameBuilder (#322)

Finish cleanup of BigDeedle code with partitioning support Add BigDee…

…dle partitioning comment to design notes Update documentation tools dependencies

BigDeedle: Materialize series on grouping and other operations BigDee…

…dle: Support resampling without materializing series Better handling of materialization via addressing schemes Refactoring and cleanup of BigDeedle code Fix bugs in ordinal virtual index SelectOptional and SelectValues can be performed lazilly

Support public fields in Frame.ofRecords

Update version number for a BigDeedle release