Add support for text with emoji

[thethtun]

When given text include emoji, the app crashed at line 61 (ZawgyiDetector.swift)

let char: Character = Character(UnicodeScalar(inputArray[offset])!)
cp = Int(char.unicodeScalarCodePoint())

Apparently, converting to UnicodeScalar has resulted in crash since initialization is force unwrapped. When input is converted into utf16 array, it counts some emoji as two items. Only the combination of two utf16 results in desired emoji.

I am not sure if this is the correct fix.
Changed code line 48 (ZawgyiDetector.swift)
from this

let inputArray = Array(input.utf16)

to this

let inputArray = Array(input.unicodeScalars)