Added a ColumnFamilyChooser to choose the column family a event should write to
Added HeaderColumnFamilyChooser which uses event headers to define the column family name
was not using HEADERS_KEY in HeaderColumnFamilyChooser, switched to use it while querying the context
Merge pull request #4 from dcapwell/issue-3

Added a ColumnFamilyChooser to choose the column family a event should w...