numlib: Hardcoded array size limit

Original Reporter info from Mantis: Ask

• Reporter name: Alexander S. Klenin

Description:

At the beginning of typ.pas:

CONST 
      highestelement=20000;

This limit is arbitrary, and quite low -- it was actually hit by one TAChart user on real data:
http://forum.lazarus.freepascal.org/index.php/topic,19777.0.html

As a stop-gap solution, I propose to increase this limit to at least 1000000.
In the future, numlib should be converted to dynamic arrays,
so this limit will disappear entirely.

Mantis conversion info:

• Mantis ID: 23816
• Version: 2.6.0
• Fixed in revision: 38357 (#b94d6444)
• Monitored by: » Vincent (Vincent Snijders)