Check that images have valid dimensions (issue 4575)
Fix special powers add-on for firefox.
Refactor - remove redundant function and all references

The function `assertWllFormed` was doing nothing different than `assert` which is
available in the same namespace. Removing it will lighten the filesize - albeit
very slightly - and reduce complexity.
Creates make.js code to build jsdoc.
Merge pull request #4614 from kalisjoshua/code-cleanup--kalisjoshua

Refactor - remove redundant function and all references
Changes 'documentload' event behavior.
Merge pull request #4617 from yurydelendik/documentload

Changes 'documentload' event behavior.
Adjusts mozcentral test files
Refactoring - remove duplicated code in TextLayerBuilder
Merge pull request #4618 from Schibum/text_layer_cleanup

Refactoring - remove duplicated code in TextLayerBuilder
Merge pull request #4616 from yurydelendik/jsdoc

Creates make.js code to build jsdoc.
Refactors buildImage to use Promise; don't draw bad images
Merge pull request #4613 from yurydelendik/buildImagePromise

Refactors buildImage to use Promise; don't draw bad images
Merge pull request #4581 from Snuffleupagus/issue-4575

Check that images have valid dimensions (issue 4575)
Setting empty tooltips for zoom select box items
Merge pull request #4621 from timvandermeij/tooltip

Setting empty tooltips for zoom select box items
version 1.0.21
Ensure that the errorWrapper is closed when a new document is opened (issue 4625)
Removes reference to the Makefile
Merge pull request #4628 from Snuffleupagus/issue-4625

Ensure that the errorWrapper is closed when a new document is opened (issue 4625)