Dev: JSHint fixes

- Primarily trailing whitespace, but undefed var as well.

- ColVis itself should be decleared only locally. It was leaking into
  global space which isn't needed.
Dev: Attach ColVis to DataTables so it can be queried
Merge branch 'master' of github.com:DataTables/ColVis
Fix #12 - Check for $.browser before using it.

- If $.browser is not present it can't be IE6...

- Interim fix, IE6/7 will be dropped in the next major version.