use dropdown for slideshow cell-type select
remove slideshow example
add a small default metaui-toolbar

just a question mark which pop-up a small text
enable dropdown preset change
convention, jQuery variable start with $

all this.xxxx = $(...) change to
    this.$xxxx

I'm thinking of potentially doing it also in parameters that are
expected to be jQuery enabled.
rename metaui -> celltoolbar
rename file metaui->celltoolbar
rename _button_list to _ui_controls_list
remove most of the duplicate example
remove relative position
do not use alert on invalid json
fix css size
remove useless jquery selector
slightly generalize utils generator
create celltoolbar in cell.js and inherit
change - to Hidden
fix lock cell button

'flase' is true while false is false
remove commented css
change set_preset to activate_preset

update docs
add default celltoolbar UI