Enforce minimum line widths
Fixed empty packet parsing bug

Packet iterator was not advanced for empty packets.
Improves rendering performance of annotation layers.

This change does the following:
 * Address TODO to remove getEmptyContainer helper.
 * Not set container bg-color. The old code is incorrect, causing it to
   not have any effect. It sets color to an array (item.color) rather
   css string. Also in most cases it would set it to black background
   which is incorrect.
 * only add border instructions when there is actually a border
 * reduce memory consumption by not creating new 3 element arrays for
   annotation colors. In fact according to spec, this would be incorrect,
   as the default should be "transparent" for an empty array. Adobe
   Reader interprets a missing color array as black however.

Note that only Link annotations were actually setting a border style and
color. While Text annotations might have calculated a border they did
not color it. This behaviour is now controlled by the boolean flag.
Merge pull request #5214 from CodingFabian/optimize-annotation-layer

Improves rendering performance of annotation layers.
Remove unused annotation highlight div

This is now done using CSS. For annotation-heavy documents this change makes the DOM much lighter.
Merge pull request #4615 from Snuffleupagus/canvas-enforce-min-line-width

Enforce minimum line widths
Merge pull request #5566 from MaMazav/Bug_fix_Empty_packet_advance_iterator

Fixed empty packet parsing bug
Merge pull request #5569 from timvandermeij/annotation-rewrite-1

Remove unused annotation highlight div
Update linting on Travis to cover *.jsm files (PR 5406 followup)

Trivial followup to PR 5406.
Merge pull request #5578 from Snuffleupagus/travis-jsm-lint

Update linting on Travis to cover *.jsm files (PR 5406 followup)