Avoid exponential time in 'mapRecurDepth'.


git-svn-id: https://fricas.svn.sourceforge.net/svnroot/fricas/trunk@1578 b0c55286-4f34-0410-a049-a1e7e93b0762
Add more operators.


git-svn-id: https://fricas.svn.sourceforge.net/svnroot/fricas/trunk@1579 b0c55286-4f34-0410-a049-a1e7e93b0762
Remove unused AUTO_GOOD_SHELL.


git-svn-id: https://fricas.svn.sourceforge.net/svnroot/fricas/trunk@1580 b0c55286-4f34-0410-a049-a1e7e93b0762