Add new Cols-based methods.
Remove unused ColumnSelection code.
Delete unused code.
Merge branch 'master' into topic/cols

Conflicts:
	modules/pframe/src/main/scala/pellucid/pframe/Frame.scala
Clean up Rec constructors.
WIP: blah
Merge remote-tracking branch 'upstream/master' into topic/cols

Conflicts:
	modules/pframe/src/main/scala/pellucid/pframe/ColumnSelector.scala
Generalize Cols code to be re-used in Rows.
Use AxisSelction for Cols.
Move AxisSelection type member to type parameter.
Add some helper methods to Cols/Rows.
Merge remote-tracking branch 'upstream/master' into topic/cols

Conflicts:
	framian-json-base/src/main/scala/framian/json/JsonExtractor.scala
	framian/src/main/scala/framian/ColumnSelector.scala
	framian/src/main/scala/framian/csv/CsvRowExtractor.scala
	modules/pframe/src/main/scala/pellucid/pframe/Series.scala
Get asArrayOf, asListOf, etc working correctly.
Add sortBy method.
Merge remote-tracking branch 'upstream/master' into topic/cols

Conflicts:
	framian/src/main/scala/framian/Frame.scala
	framian/src/main/scala/framian/RowExtractor.scala
	project/Build.scala
Clean up constructors and series joins in Frame.
Remove usages of Frame.apply from code base.
Remove Frame.apply constructor.

It's not that I don't want an apply, it's just that the default one is
silly and not useful.
Add comments for Frame constructors.
Remove dependency on JodaTime.