Changes the name of our spacing variables due to the prefixing -/_
meaning private in the use of new "use" rather than include.
All now modular too, so all variables/mixins are accessed via their
package.
Also renamed variables file to vars for simpler/cleaner access/writing.
eg. '$-m' is now 'vars.$m'
Occured when the cell contained any block content with a differnt line
height to the table cell itself.
In firefox, cells with a height would end up with an actual greater
real cell height, which messed up TinyMCE resize calculations, causing
tables to grow.
Adding default vertical-align: top, changes this behaviour to get proper
cell heights.
Related to Firefox issue: https://bugzilla.mozilla.org/show_bug.cgi?id=569645
Have tested that editor cell text align options can still be used with
this.
For #4337
- Updated editor, and other area, styles to look okay in dark mode.
- Used tinyMCE theme generator to create dark mode theme.
- Updated tinymce to latest 4x version.
- Most elements done, but still need to do editors, tables and final
pass.
- Toggled only by quick js check at the moment, checking via css media
query. Need to make into user-preference toggle.
For #1234
