Id for heading markdown is unnecessary as we didn't
attach any style/effect on that id, and it also introduce
duplicate id. So remove it from heading markdown generatiing.
* Support explicit image sizes in markdown
* Cleanup code
* Add support for missing second dimension
* Overwrite height style attribute if available, use "auto" otherwise
* Fix syntax
* Do not set the height style if its value is auto
* Re-calculate width and height, if given height is bigger than max-height
* Make formulas more explicit
* Added highlighting to links when their URL includes the search term
* Decoupling UserStore from react-router to allow for unit tests involving it
* PLT-3998 Added SiteURL as an option to be passed into the text formatting code
* Removed reference to PreferenceStore and window from TextFormatting
* Refactored TextFormatting to remove remaining browser-only code
* Updated ChannelHeader and MessageWrapper to match the changes to TextFormatting
* Increased max listeners for Preference and Emoji stores
* PLT-3832 Added automated unit tests for autolinking
* PLT-3567 Rerender posts when mention keywords change
* Updated RHS and search to match the changes to TextFormatting
* Broke TextFormatting's dependency on the UserStore
* PLT-1626 Stopped breaking up hyphenated hashtags when highlighting search terms
* Made hashtag search highlighting case independent
* PLT-1424 Improved search highlighting when searching for CJK characters
* PLT-1473 Added search term highlighting to single-line code blocks
* PLT-1473 Added search term highlighting to code blocks that don't use syntax highlighting
* PLT-1483 Added proper highlighting of at mentions
* Fixing formatting
* Removed MattermostLexer since it was exactly the same as the default marked one
* Updated list autonumbering to always start numbering from the first item's number
