Major update for external input controls #348

[ImpulseAdventure]

Major updates to support external button controls per #348

Full external button/GPIO control over the GUI is now possible by setting GSLC_FEATURE_INPUT=1

• See example: ex04_ard_ctrls_pin
• The GUI can now be in "navigation mode" or "edit mode". Selecting an advanced control (that supports the edit feature) toggles entry into edit mode, from where the forward/previous actions can navigate and manipulate the control.
• By default, the focus color is magenta and edit color is red. These can be modified by SetFocusCol().
• Extensive updates to enable full navigation and editing of XKeypad controls
• By default, a combination of touch and pin control is also possible with the "focus-on-touch" feature. It can be disabled by GSLC_FEATURE_FOCUS_ON_TOUCH=0.
• The GUI now draws an outer focus frame. In most cases, the internal contents of the element are shrunk by a pixel to accommodate the focus frame. However, for elements that cannot be "shrunk" (such as image buttons), the element dimension is expanded slightly during creation. This must be taken into account when placing elements in the Builder to avoid any potential overlap.

Changes:

• Add: enhanced integrated button support for WIO Terminal, M5stack, etc.
• Add: XKeyPad support for key glow tracking
• Add: support for element focus
• Add: default to focus-on-touch (disable with GSLC_FEATURE_FOCUS_ON_TOUCH=0)
• Add: consistent handling for focus/glow/frames (ElemCalcRectState, ElemCalcResizeForFocus)
• Add: increase element size to accommodate frames if containing images
• Change: redraw optimized to detect if any elements updated
• Change: XKeyPad focus order now made consistent with layout
• Add: support for pin assert/deassert actions
• Add: GSLC_ACTION_PRESELECT
• Add: GSLC_REDRAW_FOCUS
• Change: Element feature width widened
• Add: more color definitions