move experimental null reference checking to separate visitor

move experimental null reference checking to separate visitor

2008-04-14  Juerg Billeter  <j@bitron.ch>

	* vala/Makefile.am, vala/valaarraytype.vala,
	  vala/valaclasstype.vala, vala/valacodenode.vala,
	  vala/valadatatype.vala, vala/valaerrortype.vala,
	  vala/valaintegertype.vala, vala/valainterfacetype.vala,
	  vala/valamethodtype.vala, vala/valanullchecker.vala,
	  vala/valanulltype.vala, vala/valaparser.vala,
	  vala/valapointertype.vala, vala/valasemanticanalyzer.vala,
	  vala/valasymbolresolver.vala, vala/valatypeparametertype.vala,
	  vala/valaunresolvedtype.vala, vala/valavaluetype.vala,
	  gobject/valaccodegenerator.vala, compiler/valacompiler.vala,
	  vapigen/valagidlparser.vala: move experimental null reference
	  checking to separate visitor

svn path=/trunk/; revision=1221