CVS commit by fedemar: 

* Avoid an infinite loop when the calculation returns "nan".
* Cleaned parser.cpp a bit, x<0 isn't necessary anymore.
* User QValueList instead of an array to save the extended function attributes. I'll do that same for Parser::ufkt so the user can define more than 10 functions.

CCMAIL:kdmoeller@foni.net
CCMAIL:bmlmessmer@web.de


  M +25 -32    View.cpp   1.91
  M +0 -1      View.h   1.50
  M +7 -4      diagr.cpp   1.31
  M +2 -4      parser.cpp   1.26
  M +16 -8     xparser.cpp   1.23
  M +5 -3      xparser.h   1.23