[css mode] Fixing a vendor prefix highlighting bug

A more detailed problem description in issue #2523
[gfm mode] Stack link tokens in overlay with base tokens.

Added `combineTokens` for overlays that can override default
`combine` argument.
[real-world uses] Add ecsspert.com
Ensure current target is scrolled into view when alt-drag selecting

Issue #2518
More closer mimic Emacs behavior in transposeChars command

Issue #2507
Remove replaced code

Issue #2507
[python mode] Adjust coding style, add hintWords helper
[emacs mode] Fix test, and issue caused by test

For tranposeChars

Issue #2507
[python mode] Clean up indentation and scope tracking

Issue #2503
[neo theme] Add
[cypher mode] Add
[cypher mode] Fix coding style, remove unused code

Issue #2501
Make the set of characters that count as word characters customizeable with a helper

Issue #2426
[vim] Added support for uppercase/lowercase conversions in visual mode
[vim] Clean up visual_U/u and add tests.
merge