make the text editor view more useful

support real addline, more normally cursor move and view move,and full
support chinese rune(wide char),tested on win7, debian 6 and macos.
Merge branch 'master' of https://github.com/vzex/gocui

* 'master' of https://github.com/vzex/gocui:
  make the text editor view more useful
Merged awesome additions from vzex