This change adds support for Korean language. The keyboard layout
is based on the standard Dubeolsik keyboard layout. The keyboard
layout uses the Hangul Compatibility Jamo 3130-318F as the input
characters.

The Hangul composition and decomposition is implemented in the
Hangul support class, and has the following key features:
 - Automatic detection of initial, medial and final Jamos
   based on the current syllable
 - Handles any Unicode input sequences, not just Hangul
 - Splitting and joining of double medial and double final Jamos
 - Splitting of double final consonant and joining with following
   vowel

Added test cases that should cover most of the special cases
in Hangul input.

Change-Id: I5a6870407097bd1ce79bd2d00f81a30bd35a2f91
Reviewed-by: Mitch Curtis <mitch.curtis@theqtcompany.com>