Remove sendCommand(NORMALDISPLAY) from setContrast() (#427)

Refactor setContrast and setBrightness methods to remove forceNormal parameter and preserve display mode state

Author: jasonacox

README.md

@@ -171,7 +171,7 @@ void normalDisplay(void);
 // normal brightness & contrast:  contrast = 100
 void setContrast(uint8_t contrast, uint8_t precharge = 241, uint8_t comdetect = 64);
 
-// Convenience method to access
+// Convenience method to access setContrast with only brightness parameter
 void setBrightness(uint8_t);
 
 // Turn the display upside down

src/OLEDDisplay.cpp

@@ -784,7 +784,6 @@ void OLEDDisplay::setContrast(uint8_t contrast, uint8_t precharge, uint8_t comde
   sendCommand(SETVCOMDETECT); //0xDB, (additionally needed to lower the contrast)
   sendCommand(comdetect);	//0x40 default, to lower the contrast, put 0
   sendCommand(DISPLAYALLON_RESUME);
-  sendCommand(NORMALDISPLAY);
   sendCommand(DISPLAYON);
 }
 

src/OLEDDisplay.h

@@ -296,7 +296,7 @@ class OLEDDisplay : public Stream {
     // normal brightness & contrast:  contrast = 100
     void setContrast(uint8_t contrast, uint8_t precharge = 241, uint8_t comdetect = 64);
 
-    // Convenience method to access
+    // Convenience method to access setContrast with only brightness parameter
     void setBrightness(uint8_t);
 
     // Reset display rotation or mirroring