fix: enforce integer coeffs in rational functions
fix: better readability of version string
fix: correct test result
fix: test results
fix: test result
fix: test results
removed rField_is_Extension (alg. or trans. ext. ?)
fix: delete DEN if it is 1
Merge pull request #363 from mmklee/den

fix: delete DEN if it is 1
fix: correct usage of ..Alloc0Bin..
removed rIsExtension
Merge branch 'spielwiese' of https://github.com/jankoboehm/Sources into jankoboehm-spielwiese

Conflicts solved:
	Singular/ipshell.cc
	libpolys/polys/ext_fields/transext.cc
	libpolys/polys/monomials/ring.h
fix: need to free memory if NULL is returned
chg: port commit 7e0ad82 from master to spielwiese

commit hash in master: 7e0ad82686aab981653d1f5661ed4e7c730eaea9
was: 'chg: remove SSI_BLOCK_CHLD and SSI_UNBLOCK_CHLD'

The changes in the other two files affected by this commit have already been
ported to spielwiese.
chg: port commit e9da36a from master to spielwiese

commit hash in master: e9da36afd8cdf7d84cd5f977ba1d25e86584165b
was: 'chg: in slCleanUp(), kill the link before freeing the memory'
chg: port commit 129ed66 from master to spielwiese

commit hash in master: 129ed66a74c2b5b0201c02efbc76fa49062d2fd2
was: 'rmv: remove attribute __attribute__((noreturn)) from m2_end()'
chg: port commit f860657 from master to spielwiese

commit hash in master: f860657053f1c0d3cdf380bc47fbd8fe81f49577
was: 'chg: remove special SIGCHLD handling for HPUX_9'

The file Singular/mpsr_sl.cc, which was also affected by this commit, has
been deleted anyway, see d828d63.
rmv: remove parallel_l.tst and realclassify_l.tst

These files are almost identical to parallel_s.tst and realclassify_s.tst,
but they are not used for the tests. Already removed in master.
removed test for pselect
fix: some memory holes in gaussianElimFp/solveSystemFp