Update custom-datatypes.md
Update custom-datatypes.md
Merge branch 'dev'

* dev: (84 commits)
  Add note about upgrading
  Modify viewport meta
  A line about the coding standard.
  Optimize anchor contrast and text-rendering legibility.
  Fix responsive for mobile devices
  Small letter after comma, American Englizh
  Underscore -> Lo-Dash
  Language wash
  Better language Don't create a list just to create a list...
  Mascara was added too quickly, turned out clumpy lumpy.
  Cosmetics.
  Mark path
  It's implicit that settings are located in the settings folder.
  eZ5 lingo
  Light language wash
  Ditch hierarchy for permissions, repeat per line instead.
  Typography fixed -> revert back to lists for permissions
  Various improvements - Tweak typography (spacing) - Add screenshot for Shareable preview URLs and eZ Exceed improved links - Nicer crop for the Stack screenshot - Stuff
  Remove TinyMCE font overriding docs.
  Be explicit about the location of ezoe settings.
  ...
Improved readme
Document how to create basic toolbar applications for Exceed