Merge branch 'hotfix/0.1.11'
Merge branch 'release/0.1.12'
Merge branch 'release/0.1.13'
Merge branch 'release/0.2.0'
Aggregators compose. This adds the methods.
Fixed bug in QTreeTest
add mailing list
add archive link.
fix mailing list
Added code + test to combine tuple of aggregators into one aggregator.
FlagMonoid
OrValMonoid and AndValMonoid
simpler AndValMonoid
Merge pull request #198 from mikegagnon/flag_monoid

FlagMonoid performs logical OR
stash
ScMapMonoid
avoid instanceOf
refactor
tests for ScMap algebras
change val to def