ChangeLog

News for 4-1-0:
- new types: cring, Number (internal: CRING_CMD, NUMBER2_CMD)
- new default cring objects: ZZ, QQ, CC, RR
- operations for cring: i
  + ZZ/<int>, ZZ/<bigint>
  + ==(cring,cring)
- ringlist changed: rl[1] is of type cring
   (rl[1]=ringlist(rl[1]) gives the old representation
- ring construction extended:
  + ring r= <cring>,(<vars>),(<ord>);
  + ring r=(<cring,<vars>),...
  + def r=ringlist(<list with cring as first member>)
- charstr returns ZZ, ZZ/.., QQ, CC(...)  
- operations for Number:
  + create from int/bint/number/Number n in cring cf:
    Number(n,cf)
  + operations: +,-,*,/,% Number with Number/int/bigint
  + operation ^: Number,int
  + standard operations: string(..), print, typeof, assign
    (see Singular/iparith.inc)
- type conversion:
  + number(<Number>) -> map to current (polynomial) ring
  + cring(<Number>) -> base ring