* Initial theme
* JSON theme construction and integration with sdk project. Added theme documentation.
* Added images and review feedback
* Added internal mode and internal actions documentation
* More feedback
* Removed stub internal menu entries.
* Reduced use of images, clarified IntelliJ Platform, IDE.
* OlyaB feedback and compress images
* Moved json file to resources folder
* 19.1 -> 2019.1
* Strong note about availability of Custom UI Themes
* Removed reference to UiDefaultsHardcodedKeys.java
* Added IJSDK-567 content + cautioning UI Control keys may be deprecated.
* Better SVG icons, clarify macOS scroll bar name attributes.
* Generalize IntelliJ references, soften description of High Contrast scheme file as reference.
* Updated custom color editor scheme descriptions.
* Corrected position of editor scheme declaration.
