Delete some debugging println()'s. (almond-sh#224)

Finally figured out why my console was scrolling away every time I tab-completed something.

Merge pull request almond-sh#219 from jupyter-scala/topic/various-things

Tweaking

Check and report errors during predef (almond-sh#217)

Switch to latest Ammonite snapshot (almond-sh#215)

Includes com-lihaoyi/Ammonite#853 in particular,
which makes running several cells in a row feel much faster here

Merge pull request almond-sh#213 from jupyter-scala/topic/tweak-insta…

…ll-options

Tweak install options, and scala kernel startup

unpublished