tests: output which test file is being run
Add _SI_attrib, _SI_flags and _SI_type low-level accessors

Useful for debugging purposes
Change ring handling in SI_CallProc

Also add test cases that would lead to crashes before this change.
Update version
Fix mutability bugs
Make _SI_Matbigintmat work for mutable bigintmat
Update test cases
fetchsingular: fix wget support
fetchsingular: verify MD5 of tarball
fetchsingular: change to download Singular 4.0.0.p4
Add {configure,make}singular.debug scripts

Use these to build singular with debug flags enabled. Both install into
singular/dst to make it easy to switch between the two: Just run
  ./makesingular && make
or
  ./makesingular.debug && make
to (relatively) quickly switch between normal and debug mode. (To make
it even faster, remove the "make check" from your copy of makesingular).
libsing.h: #include assert.h
Remove mmInit

Neither Singular 4.0.0.p4 nor Singular.git need it anymore
Remove unused m4/libpolys-check.m4
configure: modernize cygwin check
Rewrote the LB_CHECK_LIBSINGULAR m4 macro

It should be much more robust now. Moreover, we actually
check the libSingular version now, if requested, and do
other fancy stuff.
Simplify startup initialisation code

In particular, get rid of the kernel function _SI_INIT_INTERPRETER, the
GAP function _SI_InitInterpreter and the files SINGULARPATH and
SINGULARPATH.in
oops: remove static decl or _SI_ErrorCallback
Do not print confusing 'deg' for ideals
Add missing SI_vector method invoking SI_vector_singular