Gutenberg Inline Editing

• Added: Gutenberg inline highlighting support (RichText format)
• Added: border around Enlighter Gutenberg codeblock (default theme)
• Added: resource urls of the theme-customizer and DRI are resolved by ResourceManager::getResourceUrl to allow optional filtering via enlighter_resource_url
• Added: support for Jetpack markdown (codeblocks will be excluded from jetpack gfm processing)
• Added: multiversion travis-ci lint checks
• Changed: trailing slash from global constant ENLIGHTER_PLUGIN_URL has been removed
• Changed: wp-skeleton updated to v0.27.0
• Changed: WordPress readme.txt is generated by wp-skeleton to avoid format issues (merged readme+changelog)
• Changed: updated Gutenberg plugin to v1.1.0
• Changed: removed contextual help content if favor of the official documentation
• Bugfix: double slashes are used in the paths of DRI and theme customizer resources
• Bugfix: escape sequence were transformed into their characters in recent Gutenberg releases
• Bugfix: a comma caused the plugin/wordpress to crash in legacy php 7.2 (lint checks of php 7.3 worked without any issues)