Added missing DIV operator, added suggestion for new lhs_rhs_element
Added better vector processing support to scheduler. x = y1 + y2 + y3 + y4 now working.

Implementation was refined such that the logic can now also operate on subexpressions.
This is achieved by passing the root node explicitly, hence subexpressions are easily obtained
by passing a modified root node. Matrix operations essentially unchanged.
Merge remote-tracking branch 'upstream/master' into pyviennacl
Fixed wrong project name in CTestConfig.txt
Merge remote-tracking branch 'upstream/master' into pyviennacl