Bug #617660: Improving iso-4217-currencies

Patch by Frank H. Ellenberger

1. improve the header of fieldnames with annotations
2. sort by ISO code, because
   a. easier for non english people
   b. most tables in the internet have this sort order.
      So maintainance becomes easier.
3. inserting a Column local_symbol, because some people like to use it, e.g.
   https://bugzilla.gnome.org/show_bug.cgi?id=492417#c3
   But probably there is a better way to get this informations.
4. Review List:
   a. adding: CDF, GHS, ...
   b. outdated: AON->AOR->AOA, GWP->XOF, ...
   c. Typos like "fening".
   d. Alway use singular instead of a mixture.
5. add comments:
   a. outdated currencies prepared as in the header shown.
   b. for abbreviations.

Background is the thread starting with
https://lists.gnucash.org/pipermail/gnucash-devel/2009-October/026558.html

git-svn-id: svn+ssh://svn.gnucash.org/repo/gnucash/trunk@19120 57a11ea4-9604-0410-9ed3-97b8803252fd