fix: memory leak while calling gcd with a term and a non-term poly
new: division and gcd of integer polynomials via factory

added conversion functions between integer polynomials in Singular and Factory
extended the singclap_gcd and singclap_pdivide functions to cover the case where
ground ring is integer
Merge pull request #619 from YueRen/gcd_fixes

Gcd fixes (gcd for poly over Z)
Merge pull request #625 from mmklee/char_series

Char series
removed HAVE_FACTORY: always true
use static for conversion routines integer <->factory
changes for alternate integer representation
removed cfName and related
print(ring/cring)
bugfix for 613
bugfixes for 583, 611, 632
fixed another option modifying bug and added a test
test for ticket 256 and small bugfixes
add tests related to ticket 469
Merge pull request #626 from surface-smoothers/fix.613

bugfix for ticket 613
fixing f3149e13175bee0d8ebd2653e9c18f2b0496ddbb (tr.613)
tests: print(ring/qring)
fix basering change in algebra::is_injective
Merge pull request #627 from surface-smoothers/spielwiese

bugfixes for tickets 583, 611, 632
missing parts for dccf2b7858608f2bcc2740c336f09a1482164db8 (tr.583,611,632)
fix tr.635 (max-min is limited by 2^31)