Merge pull request #251 from alexanderdreyer/master-pyobject

Fix: avoid infinite recursion, if pyobject.so is broken
fix: porting singnal handling (win, etc.)
chg: estimate term growth through shifting evaluation point in ezgcd
fix: stupid bug in ezgcd
chg: faster gcd computation in EZGCD in corner cases
chg: switch to sparse modular GCD in some cases
fix: bad condition
chg: tuning parameter in sparseGCDFp
chg: switch to dense modular GCD
opt: subst improved
opt: map improved (includes substitute etc.)
chg: updated test results
Merge pull request #260 from mmklee/factory_gcd

Factory gcd
fix: GP: avoid warnings about SB
chg: set blocks to keep to 0 for OM_NDEBUG or __OPTIMIZE__
fix: omfree -> omFree (from spielwiese)
 fix: compiler warning
opt: omfree -> omFree
Avoid empty wildcard pattern in Makefile
Replaced some system calls by safely wrapped versions
Special handling of nanosleep
Systematically checking for missing wrapped interupable system calls