Fix standalone Lua script screen flicker and improve error messages (#982)

* Relax assumptions about when Lua is called in foreground and background

* Start Lua cycle timer both in foreground and background
Do not assume that background/foreground alternates

* Lua is called at every Standalone GUI cycle instead of 5 Hz
Since Lua preempts every 50 ms or so, the GUI should remain responsive.

* In standalone script, only call Lua once per GUI cycle, to avoid messing up buffer handling.

* Revamped error reporting for Standalone and Telemetry Lua scripts

* Font size for Lua error is reduced from XL to L on color if LCD_W < LCD_H

* In drawTextLines, also possible linebreaks for opening brackets.

* Smaller font for error message on tall color screen

* Make titlebar height match font size on narrow LCD

radio/src/gui/common/stdlcd/popups.cpp

@@ -50,7 +50,7 @@ void drawMessageBoxBackground(coord_t top, coord_t height)
 void drawMessageBox(const char * title)
 {
   // background + border
-  drawMessageBoxBackground(MESSAGEBOX_Y, 40);
+  drawMessageBoxBackground(MESSAGEBOX_Y, 48);
 
   // title
   lcdDrawSizedText(WARNING_LINE_X, WARNING_LINE_Y, title, WARNING_LINE_LEN);