ByPassNode introduced

A fix-up of the warning conditions in BypassNode

The contains method added to TypeExpr

empty vector mappers added

The first half of the cast pipelines fixed to bypass RNull and RMissing

a fix-up in CastBuilder.getCasts() method

The second half of the cast pipelines affected by the new RNull and RMissing handling fixed.

FindFirstNode invoked directly from the BypassNode; all pipelines wrapped by the BypassNode

rebased on master

The bypassReady step removed

Formatting issues fixed in RBuiltinDiagnostics

Style issues fixed in BypassNode