Don't carry two vector<>s on GotoElements that don't need them.

The interface of CommandElement required passing references to vectors. Change
the interface so goto elements that only have a single id/pointer don't pay the
overhead of keeping two vector<>s.
Dump raw bytes when we encounter an unparsable in an unimplemented opcode.
Add minimal support to dump how rlvm parsed a seen for debugging.

Use --dump-seen to make rlvm act like a disassembler. I've tried to make
the dumped code look as much like kepago as possible, but it doesn't even
do name resolution (which is probably a good thing in any debugging situation
where its needed.)
Experimental: Implement the three z-ordering properties on objects.
Fix the order of duration_time and delay.
Fix implementation of objDispCorner.

Which overloads did what was incorrect.
Add an alpha mutator, too.
Implement SetFontColour
Fix wrong opcode numbers on new nowait commands.
Add preloading commands for g00 and clean up how we load files.

This pushes caching details up from SDLGraphicsSystem to GraphicsSystem.
Fix all occurrences of duplicated opcodes.

Add debug build check to make sure we don't have duplicated opcodes.
Fix the LB test Rin-bad.lua
Add more object property getters and clean up the file they're in.
Parser change: Deal with two quoted strings right next to each other.

In LB, SEEN9600, line 1137, there's a call to objOfFileGan where two of its
string arguments don't have a comma between them. This fixes that.