[match-highlighter addon] Use primary selection, not first one

Closes #2539
[markdown mode] Fix code block styling after indented line
[markdown mode] Fix XML styling in Markdown mode

Fix the condition when XML styling should be invoked.
Also add test cases.
[dylan mode] Add module loading shim

Closes #2533
[vim] Visual paste operation with unit tests
[vim] support for append action command in visual mode added
[vim] Resolve upward selection bug
Abort wheel delta measurement when scrolling explicitly

Issue #2537
[sublime keybindings] Don't include zero-char selection bottoms in swapLine*

Issue #2542
[javascript-hint addon] Support an option that disables use of the current global scope
[css mode] Add more CSS Shapes properties

Add shape-image-threshold and shape-margin.
[real-world uses] Add Better Text Viewer and CrossUI
Add license and version comment to all scripts
Fix bug in release script
[show-hint addon] Fix a typo