chg: defer shutdown in slClose()
(cherry picked from commit 96d98ec5e074988d6acae83de7646fc65aa7382b)

Signed-off-by: Andreas Steenpass <steenpass@mathematik.uni-kl.de>

Conflicts:
	Singular/silink.cc
Merge pull request #433 from steenpass/slClose_sw

chg: defer shutdown in slClose()
chg: singularsurf/surf/display instead of gtk-surf
chg: do another waitpid() after nanosleep() succeeded
(cherry picked from commit 9d9a7faa6bb7522c1db8caabc4c47c0aa0840caf)

Signed-off-by: Andreas Steenpass <steenpass@mathematik.uni-kl.de>
fix: return NULL for non-bb-types (op2: 1st OR 2nd op is of bb type)
Merge pull request #435 from steenpass/waitpid_sw

chg: do another waitpid() after nanosleep() succeeded
fix: ring dep. stuff in newstruct: send/receive via links (ssi:6)

from master
chg: procdir path for debian
Removed temporary files
better message text in checklibs (texinfo)
some adaption to 4-0-0
doc: more index entries for linear algebra
fix: typo
fix BS: include singular.spec in dist file
removed: outdated README/INSTALL stuff
removed: more outdated README/INSTALL stuff