account separator character name untranslated

[Christian Stimming]

David,

thanks a lot for the unicode-ization of the account separator character. One 
issue, however, was introduced through this: When choosing one of the 
proposed characters, one has to enter the pre-defined english long names into 
the preference. That is, well, not quite suitable for the translated gnucash, 
as non-english speakers will surely not know what "colon" stands for...

Either we make these names to be translated as well, or we completely drop the 
pre-defined strings altogether, at least from the human-readable 
documentation in "preferences". It might be fine to keep it internally 
though, but it should be dropped from the documentation.

Also, the example account in the preferences should IMHO better not be 
composed of three separate strings but rather one printf-string, as in 
"Income%sSalary%sTaxable". This way translators can choose other combinations 
of account names which are more common in their languague.

Christian