add a method to supplement descriptions with unofficial 'aliases'
add a method to supplement descriptions with unofficial 'aliases'

- this is to solve the problem that people search for 'umlaut' but the
  term is not used at all in the Unicode Character Database
- this commit changes the character description from:
    DIAERESIS
  to:
    DIAERESIS (OR UMLAUT)
  the intended meaning is that the two dots might represent a diaeresis or
  they might represent an umlaut
- this particular aliasing is not applied to characters which are
  identified as Greek in the description

grantm/ucf,grantm/ucf,grantm/ucf