Optimization: color_blend() (#4245)

Removing the bool saves on code size and makes the function a tiny bit faster. Also this is a cleaner solution IMHO.

-updated blend function to optimized 8bit calculation
- efficient color blend calculation in fews operations possible
- omitting min / max checks makes it faster on average
- using 8bit for "blend" variable does not significantly influence the resulting color, just transition points are slightly shifted but yield very good results (and better than the original 16bit version using the old fastled math with improper rounding)
- updated drawCircle and drawLine to use 8bit directly instead of 16bit with a shift

wled00/fcn_declare.h

@@ -78,7 +78,8 @@ class NeoGammaWLEDMethod {
 };
 #define gamma32(c) NeoGammaWLEDMethod::Correct32(c)
 #define gamma8(c)  NeoGammaWLEDMethod::rawGamma8(c)
-[[gnu::hot]] uint32_t color_blend(uint32_t,uint32_t,uint16_t,bool b16=false);
+[[gnu::hot]] uint32_t color_blend(uint32_t c1, uint32_t c2 , uint8_t blend);
+inline uint32_t color_blend16(uint32_t c1, uint32_t c2, uint16_t b) { return color_blend(c1, c2, b >> 8); };
 [[gnu::hot]] uint32_t color_add(uint32_t,uint32_t, bool fast=false);
 [[gnu::hot]] uint32_t color_fade(uint32_t c1, uint8_t amount, bool video=false);
 CRGBPalette16 generateHarmonicRandomPalette(CRGBPalette16 &basepalette);