Now extended range for weight, offset also without GVARS, GVARS fix, overruns fix

This version holds mainly bugfixes and prepares this branch for merge.
Please test and report.

- gvars didn't work for value ranges usually from -100 to 100 (e.g. diff function)
- gvars shown wrong also in models menu (same in trunk as well)
- gbirkus tested ranges with speed optimizations, overruns occured at half range of trunk version. Now this is fixed and a much bigger range can be used. Still overruns possible. Please test.
- ISR 10msec now safe and code optimized.

src/menus.cpp

@@ -706,10 +706,10 @@ int16_t gvarMenuItem(uint8_t x, uint8_t y, int16_t value, int16_t min, int16_t m
   return value;
 }
 #else
-int8_t gvarMenuItem(uint8_t x, uint8_t y, int8_t value, int8_t min, int8_t max, LcdFlags attr, uint8_t event)
+int8_t gvarMenuItem(uint8_t x, uint8_t y, int8_t value, int16_t min, int16_t max, LcdFlags attr, uint8_t event)
 {
   lcd_outdezAtt(x, y, value, attr);
-  if (attr&INVERS) CHECK_INCDEC_MODELVAR(event, value, min, max);
+  if (attr&INVERS) value = checkIncDec(event, value, min, max,EE_MODEL);
   return value;
 }
 #endif