add: modular.lib
Merge pull request #554 from steenpass/modular

add: modular.lib
add: Tst/Short/modular_s.tst to ok_s.lst
fix: tr.590
fix: readline undef use with TAB ab start of line
fix: tr.588  reconsidered (syz,intersect,modulo and returnSB)

Conflicts:
	Singular/iparith.cc
	kernel/ideals.cc
tests for dumb things: tr.590,588,579,576
fix: sw-master syntax diffs
fix: set data to NULL for sysvar (LastPrinted), which may be a pointer
fix: different error msg,
fix: removed duplicate rSetSyzComp
fix: rinvar/returnSB on syz
fix: rinvar/Typ()