add icons, scrollbar and metronome. Sort items by apparence time.
when more than one script in _NB found, we use the last one instead of displaying an error. This way, we can annotate documents who contain other scripts ending in _NB,
such as documents generated with NB !
add link to add HTML
import icons for video player
Merge branch 'video'

Conflicts:
	content/data/icons/png/default_theme.png
	content/data/icons/theme_light.svg
	content/modules/dev/pers2.js
	content/modules/dev/ui.docView11.js
	content/modules/dev/ui.docView5.css
	content/modules/dev/ui.notepaneView11.js
	content/ui/admin/step22.js
add LabelCategory captions, to make labeling less error prone (short mmemonic instead of 0,1,2)