fixed another option modifying bug and added a test
test for ticket 256 and small bugfixes
add tests related to ticket 469
fix basering change in algebra::is_injective
Merge branch 'fix.baseringchange.algebra.is_injective' of https://github.com/surface-smoothers/Sources into surface-smoothers-fix.baseringchange.algebra.is_injective

Conflicts:
	Tst/Short.lst
Merge branch 'surface-smoothers-fix.baseringchange.algebra.is_injective' into spielwiese
Merge pull request #629 from surface-smoothers/work.on.ticket.529

fixed another option modifying bug and added a test (tr.529)
fix: test result
Merge pull request #630 from surface-smoothers/genus.minor.bug

test for tickets 259 and 469; fix adding R+Rhelp
minpoly only for univariate polynomial rings
fixed: some missing types in proc declarations
fix: gcd over integers of two terms ignoring coefficients
Merge pull request #634 from YueRen/gcd_fixes

fix: gcd over integers of two terms ignoring coefficients