* Move int range checkers from options class to common file
* Improve error handling and reporting
* Make some minor improvements to init and test suite
* Fix 'trypewriter' to 'typewriter' typo
* Remove menu path description in dialog help text
* Improve the help text for entries in the Format menu
* Reword a couple of dialog messages
* Drop the subfolders for GUI themes
* Remove bundled font support
* Add safe file read function
* Allow loading themes from multiple locations
* Clean up unused variables
* Clean up icons class
* Merge icon theme icons
* Update icon theme class
* Remove guiDark config setting
* Fix tests
* Fix handling of default theme
* Update icon readmes
* Add test for getGuiItem common function
* Update instructions and readmes
* Cleanup in base files
* Cleanup in core files
* Cleanup in gui files
* Cleanup in dialog files
* Cleanup in tools files
* Cleanup in test files