Fix for NumericInput height

Issue was due to conflict in bootstrap.css, so sourcing it from shared.R
fix insert-new-cell button

was broken by late loading of command prompt
took the opportunity to move code in there
fixes #950
remove unneeded style
don't let fork_of text get too big

while we're at it, update the max size fo the notebook title itself
(which is still horribly hard coded for 1440 pixel wide screen)
fixes #962
Merge pull request #961 from GanapatiBhat/develop

Fix for NumericInput height