Fix 'narrowing' compiler errors on Teensy

Adafruit_NeoPixel.cpp

@@ -2181,15 +2181,15 @@ void Adafruit_NeoPixel::clear() {
 // It exploits features of GCC's preprocessor to generate a PROGMEM
 // table (in flash memory) holding an 8-bit unsigned sine wave (0-255).
 static const int _SBASE_ = __COUNTER__ + 1; // Index of 1st __COUNTER__ below
-#define _S1_ (sin((__COUNTER__ - _SBASE_) / 128.0 * M_PI) + 1.0) * 127.5 + 0.5,
+#define _S1_ (uint8_t)((sin((__COUNTER__-_SBASE_)/128.0*M_PI)+1.0)*127.5+0.5),
 #define _S2_ _S1_ _S1_ _S1_ _S1_ _S1_ _S1_ _S1_ _S1_ // Expands to 8 items
 #define _S3_ _S2_ _S2_ _S2_ _S2_ _S2_ _S2_ _S2_ _S2_ // Expands to 64 items
 static const uint8_t PROGMEM _sineTable[] = { _S3_ _S3_ _S3_ _S3_ }; // 256
 
 // Similar to above, but for an 8-bit gamma-correction table.
 #define _GAMMA_ 2.6
 static const int _GBASE_ = __COUNTER__ + 1; // Index of 1st __COUNTER__ below
-#define _G1_ pow((__COUNTER__ - _GBASE_) / 255.0, _GAMMA_) * 255.0 + 0.5,
+#define _G1_ (uint8_t)(pow((__COUNTER__-_GBASE_)/255.0,_GAMMA_)*255.0+0.5),
 #define _G2_ _G1_ _G1_ _G1_ _G1_ _G1_ _G1_ _G1_ _G1_ // Expands to 8 items
 #define _G3_ _G2_ _G2_ _G2_ _G2_ _G2_ _G2_ _G2_ _G2_ // Expands to 64 items
 static const uint8_t PROGMEM _gammaTable[] = { _G3_ _G3_ _G3_ _G3_ }; // 256