style: Fixed most styles (according to standardjs)

Conversions/DecimalToBinary.js

@@ -1,5 +1,5 @@
 function decimalToBinary (num) {
-  var bin = []
+  const bin = []
   while (num > 0) {
     bin.unshift(num % 2)
     num >>= 1 // basically /= 2 without remainder if any

Conversions/HexToRGB.js

@@ -1,12 +1,12 @@
 function hexStringToRGB (hexString) {
-  var r = hexString.substring(0, 2)
-  var g = hexString.substring(2, 4)
-  var b = hexString.substring(4, 6)
+  let r = hexString.substring(0, 2)
+  let g = hexString.substring(2, 4)
+  let b = hexString.substring(4, 6)
 
   r = parseInt(r, 16)
   g = parseInt(g, 16)
   b = parseInt(b, 16)
-  var obj = { r, g, b }
+  const obj = { r, g, b }
 
   return obj
 }

Conversions/RomanToDecimal.js

@@ -1,4 +1,4 @@
-var values = {
+const values = {
   I: 1,
   V: 5,
   X: 10,