Spirik GEM Versions Save

• AppContext struct renamed to GEMContext (with backwards compatibility with previous name);
• New methods ::setDrawMenuCallback() and ::removeDrawMenuCallback() for managing optional callback that is invoked at the end of ::drawMenu() call;
• Method ::getCurrentAppearance() made public;
• private access specifiers changed to protected to make it possible to access internal fields and methods from within user-defined derived (inherited) classes, allowing to extend functionality of GEM;
• Optional "Advanced Mode" introduced, disabled by default but can be enabled via config.h or GEM_ENABLE_ADVANCED_MODE flag; when enabled some of the internal methods are made virtual to make it possible to override those methods in own sketch, allowing further customization and modification of GEM; more features of Advanced Mode may be added in the future;
• Readme updated accordingly.

• Support for custom fonts via ::setFontBig() and ::setFontSmall() methods of U8g2 and Adafruit GFX versions of GEM;
• Support for UTF8 fonts for U8g2 version of GEM via GEM_u8g2::enableUTF8() method (only for menu titles and menu item labels);
• Readme updated accordingly.

• Possible breaking change: AltSerialGraphicLCD version disabled by default, but can be enabled explicitly via config.h or build flag GEM_ENABLE_GLCD;
• GEMAppearance struct, ::setAppearance() methods added; ability to set appearance for menu pages individually and change it at a runtime;
• GEMPage::getMenuItem() and GEMItem::getMenuItemNext() methods made public for easy menu items traversing from the sketch;
• ::getCurrentMenuPage(), GEMPage::getCurrentMenuItem(), GEMPage::getCurrentMenuItemIndex() methods added to target currently selected menu item (can be useful for certain callback functions);
• GEMItem::setAdjustedASCIIOrder() method added for more suitable order of characters when editing text variables in certain use cases;
• Example 06: Todo List added;
• Readme updated accordingly.

• Ability to remove menu item from menu page via GEMItem::remove() method;
• Ability to re-add menu item to menu page (same or different) via subsequent call to GEMPage::addMenuItem() method;
• Passing additional parameters to GEMPage::addMenuItem() method allow to add menu item at a specified index pos out of total (total set to true) or only visible (total set to false) items of the menu page;
• Correctly handle attempts to add menu page to multiple parent menu pages (now it is possible to change parent menu page);
• Available constructor options clarified in Readme and examples;
• Readme updated accordingly.

• Support for chaining of method calls;
• Ability to specify parent menu page via GEMPage constructor;
• Readme updated accordingly.

This release contains code refactoring, there is no functional changes.

• -Wmissing-field-initializers warning fix;
• boolean data type ditched in favor of bool;
• Readme clarifications.

• Examples on how to control menu with rotary encoder.

• Support for option to invert keys (resulting in an inverted order of characters) during edit mode via ::invertKeysDuringEdit() method;
• Readme updated accordingly.

• Support for setting text 'magnification' size (i.e. scale factor) for Adafruit GFX version via ::setTextSize() method;
• Readme updated accordingly;
• Simplify Party Hard example for Adafruit GFX version by commenting out one of the frames to free up some program storage space to fit into Arduino UNO R3.

• Explicit inclusion of avr/dtostrf.h for RP2040 and nRF52840 based boards (to allow support for floating-point variables);
• -Wreorder, -Wunused-variable, -Wmaybe-uninitialized warnings during compilation for RP2040 and nRF52840 fixes;
• Compatibility section in Readme updated.