Fixes #5, added command `ctbl:navi-jump-to-column'.
Improved function `ctbl:navi-jump-to-column' by following https://github.com/kiwanami/emacs-ctable/issues/5#issuecomment-27319374
Fix ctbl:navi-jump-to-column
Merge pull request #6 from RenWenshan/master

Fixes #5