Add more operators.
Rename 'limitedint' to 'logint', etc.
Change default style of 3D graphics.
Better zero test during limit computation.
Change formula for derivatives of asec, asech, acsc and acsch.
Better handling of algebraic integrals.
Generalize 'kernels' and 'tower'.
Do not signal errors on complex integration result.
Fix trivial case in Ei code.
Comparable instead of OrderedSet in FreeModule