[PDFHistory] Prevent the history from getting stuck in certain edge cases
Prevent named actions from displaying a 'resource://' URL in Firefox
Avoid triggering rendering multiple times when zooming using the mouse wheel
issue #3346

squashing commits.
Merge pull request #3421 from Snuffleupagus/avoid-multiple-rendering-on-wheel-zoom

Avoid triggering rendering multiple times when zooming using the mouse wheel
Merge pull request #3618 from Snuffleupagus/followup-3557

Prevent named actions from displaying a 'resource://' URL in Firefox
Merge pull request #3507 from Snuffleupagus/PDFHistory-fix-multiple-identical-states

[PDFHistory] Prevent the history from getting stuck in certain edge cases
Secondary toolbar
Merge pull request #2792 from timvandermeij/settings-bar

Secondary toolbar
Prevent searching during load from breaking the find functionality
Simplify getVisiblePages() in presentation mode
Update the Swedish l10n with secondaryToolbar strings
Merge pull request #3646 from Snuffleupagus/secondaryToolbar-l10n-Swedish

Update the Swedish l10n with secondaryToolbar strings
Merge pull request #3644 from Snuffleupagus/presentationMode-simplify-getVisiblePages

Simplify getVisiblePages() in presentation mode
Merge pull request #3607 from Snuffleupagus/issue-3604

Prevent searching during load from breaking the find functionality
Update readme with what files are needed.
Annotation selection
Fix searching in presentation mode in Firefox
Merge pull request #3431 from timvandermeij/annotation-selection

Annotation selection
Merge pull request #3645 from Snuffleupagus/presentationMode-fix-search

Fix searching in presentation mode in Firefox