Taked the softKeyboard code, the application that android developers
give as example, as base.
The only change is include the min version in AndroidManifest
it was not work on versions belower kitkat. Corrected
KIS: removed all the code related with autocomplete text
Renamed the packages from com.example.android.softkeyboard to
es.csc.android.hexakey
Changed all the references from Soft KeyBoard to HexKey
Adapted the name of private variables to my style