Merge branch 'master' of https://git.code.sf.net/p/maxima/code
$trace: improve tracing of Lisp functions
Improve simplification of signum and abs of signum powers
Merge branch 'master' of https://git.code.sf.net/p/maxima/code
Merge branch 'master' of https://git.code.sf.net/p/maxima/code
signum(x) has a discontinuity at x = 0
Prepare for integrate being able to handle abs
is(equal(1/z, 0)) = unknown for complex z