Redusing the list of selectable languages

[Petter Reinholdtsen <pere@hungry.com>]

I've decided to cut the language list short while we wait for bug
#188043 to be fixed.  I believe 20 entries is a safe maximum value to
use.  The list is reduced from 43 entries to 19.  The languages left
are picked partly based on two criteria

  - The language is in use by some of the d-i developers
      (da_DK, en_US, fi_FI, fr_FR@euro, de_DE@euro, lv_LV, se_NO,
       no_NO, nn_NO, pt_BR, sv_SE)

  - The language uses a problematic charset which we need to fix
      (zh_TW, hu_HU, is_IS, ja_JP, ko_KR, pl_PL, ru_RU, es_ES)

Any comments on the languages selected.  The following languages was
removed from the list:

  ca_ES zh_CN hr_HR cs_CZ nl_BE nl_NL en_AU en_IN en_GB eo_EO
  fr_BE@euro fr_CA fr_LU@euro fr_CH gl_ES he_IL ga_IE it_IT pt_PT
  sv_FI tr_TR

Is the set of "problematic" languages long enough?