Further consolidated method calls.
Merge pull request #56 from nomothetis/fix-above-line-completion-position

Completion alignment improvements

 - Properly aligns the completion window to the beginning of the string, across
   font size changes.
 - Shows the window above or below the current line, depending on available
   space.
 - Never takes up more than half the sreen with the completions; scrolling is
   enabled to see more.
 - Changes the colors of the currently selected completion to make it more legible.
Merge branch 'master' into keep-completion-window-after-backspace