jsshell: first commit
config object to preventExtensions
add comments
implement toStringResult
update edito settings, add debug log and comments
implement history operation

 * `Ctrl + p`: previous
 * `Ctrl + n`: next
fix: esprima.js path
update header
fix: comtext menus
update style
implement showing elapse time

  please execute `config.timer = true`
remove unnecessary global funciton
Merge branch 'jsshell'
Merge branch 'master' of github.com:teramako/teramako.github.com