added readme
Update README.md
added a convenience utility to build maps fluently
added union
changed getOrElse meaning on none options.
added some more resulting list functions
Merge remote-tracking branch 'upstream/master'
Merge pull request #1 from local-ch/MiK

new standard predicates and functions
Merge pull request #2 from local-ch/MiK

default accumulators - sum, product, joinOn
Merge branch 'master' into MiK