Fixing incorrect substring indexes (#431)

Substring indexes were all off by 1, creating an incorrect output. Also removed unnecessary `toUpperCase()` calls.

Author: abney317

Conversions/HexToRGB.js

@@ -1,7 +1,7 @@
 function hexStringToRGB (hexString) {
- var r = (hexString.substring(1, 3)).toUpperCase()
- var g = hexString.substring(3, 5).toUpperCase()
- var b = hexString.substring(5, 7).toUpperCase()
+ var r = hexString.substring(0, 2)
+ var g = hexString.substring(2, 4)
+ var b = hexString.substring(4, 6)
 
  r = parseInt(r, 16)
  g = parseInt(g, 16)
@@ -11,4 +11,4 @@ function hexStringToRGB (hexString) {
  return obj
 }
 
-console.log(hexStringToRGB('javascript rock !!'))
+console.log(hexStringToRGB('ffffff'))