revert to using jquery

minor perf gain can't mean much here (since we are building these on demand now
tweak appear commands

put commands in wrapper span and float it right
don't try to measure width (possible fix for #905)
white out entire date area for cleaner look
only show notebook commands when on actual node

not on history nodes under it
(if those had commands they would be different)
fixes #873
hide date don't white it out

just simpler, and now appear width can be exaggerated
re-enable cmd-S for view mode

the notebook can't have changed, and people might want
to save as html in view mode

@sujitbehera27, unfortunately we always have to think "what about
view mode?" when writing any UI code.  here we probably don't to
disable the default browser functionality in view mode
update NEWS and organize 1.2 changes into sections