Allow suppression of alt and dimension fields in image plugin.
Non-negative settings requiring explicit `false` for suppressing image fields.
Allow suppression of alt source, poster, and dimensions fields.
Protect against missing alt source and poster fields.
Non-negative settings requiring explicit `false` for suppressing media fields.
Fixed bug where tabindex on elements within the editor contents would cause issues on some browsers.
Added some unit tests to the tabindex fix.
Fixed bug where link text wouldn't be properly updated in gecko if you changed an existing link.
Added new table_grid option that allows you to disable the table grid and use a dialog.
Fixed a event order bug in MenuItem.js
Merge pull request #348 from Kindling/patch-media-settings

Allow suppression of alternate source, poster, and dimension fields in media plugin.
Merge pull request #346 from Kindling/patch-image-settings

Allow suppression of alt and dimension fields in image plugin.
Updated changelog.txt.
Relabeled Columns to Cols since they are already present in i18n packs.