[svn r335] The basics of exception handling are in place.

Still need to make sure calls are turned into invokes everywhere. (NewExpression for instance)
Still some rough edges and corner cases to figure out.
Needs testing!

gen/irstate.h

@@ -136,8 +136,11 @@ struct IRState
     llvm::BasicBlock* scopeend();
     bool scopereturned();
 
+    // landing pads for try statements
+    typedef std::vector<llvm::BasicBlock*> BBVec;
+    BBVec landingPads;
+
     // loop blocks
-    typedef std::vector<IRScope> BBVec;
     typedef std::vector<IRLoopScope> LoopScopeVec;
     LoopScopeVec loopbbs;