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
First pass at better CSV parser.
Csv -> Frame support and bug fixes.
Add missing apply 3 case to AxisSelection.
Get asArrayOf, asListOf, etc working correctly.
Better guesses at empty/invalid cells.
Deal with labeled frames in a sane way.
Merge pull request #23 from ezhulenev/master

Fix README.md libraryDependencies
Include whole row as context in CSV errors.