content import: themes, slides, cell parts

[bollwyvl]

As a User, I want to reuse slides, cell content, backgorunds, themes, fonts from one or more other presentations

Many types of things should be importable:

• slides
• cell parts (crazy)
• themes
  • palettes
  • fonts
  • backgrounds

Basically, it should be possible to either use an URL or a drag-dropped .ipynb to import all (or part of) that type of data into the appropriate place in the UI.

two types of import should be possible (and potentially not mutually exclusive):

• link, where a url is maintained. could be relative, i.e. ./theme.ipynb
• embed, where the full content is loaded

Once loaded, imported content should either be:

• locked (used totally by reference)
• copied (i.e. changeable, no longer updateable)
• patched (i.e. import this slide layout, make region 2 50% smaller)