lemon-1.2: Graph

Merge 2011-12-20, by Alpar Juttner
LEMON 1.2.3 released (9e587caed953 tagged as r1.2.3) 1.2 2011-11-09, by Alpar Juttner
Unify sources 1.2 r1.2.3 2011-11-09, by Alpar Juttner
Update NEWS file 1.2 2011-11-09, by Alpar Juttner
Merge bugfix #430 to branch 1.2 1.2 2011-11-01, by Alpar Juttner
Fix LpBase::Constr two-side limit bug (#430) 2011-11-01, by Gabor Retvari
Merge #428 and #429 to branch 1.2 1.2 2011-10-24, by Alpar Juttner

lemon-1.2