Add AST-based deobfuscator #7

Remaining items:

Add proper support for multiple passes (running AstDeobfuscator twice changes some code the second time, but it should not)
Fix transforming of long expressions (e.g. a + b + c) - might be covered by the item above?
Fix int var16 = var15 - (-16 - var0.anInt3400); (presumably that's an example of the item above?)
Rewrite simple identities (e.g. 0 - x to -x, x + 0 to x, x * 1 to x and so on)
Improve Fernflower's choice of char/hex/decimal literals
Remove redundant casts
Rewrite > and >= in for loops to < and <=
~~Rewrite > and >= in while and do/while loops~~ I think I'm going to ignore this for now, as it's probably fairly difficult to figure out whether < or > is more appropriate and it'd be nice for the AST deobfuscator to not change things a human might manually tidy up in the IDE.
Use > and >= in for loops that decrement instead of increment
Rewrite return x ? y : z; in an else block (or an if followed by an else) to use else if instead
Rewrite pre-increments to post-increments where possible
Improve structuring in general (e.g. try to rewrite if and else blocks to avoid almost the entire body of a method being indented, etc.)
Remove use of deprecated methods (e.g. new Integer(...) -> Integer.valueOf(...), newInstance()) (note: in the future we might want to do this at the bytecode level in the bundler instead)
Rewrite (long) 0 -> 0L
Rewrite (x << 24) & 0xFF000000 -> (x & 0xFF) << 24
Rewrite sum >>> 11 & 0xAF400003 -> sum >>> 11 & 0x3
Rewrite codeword << -bitPos5 -> codeword >>> bitPos5 (is that equivalent?) (ditto @Pc(79) int local79 = local19 & -bitPos >> 31;)

	private static String method892(@OriginalArg(1) int arg0) {
		if (arg0 >= 100000) {
			return arg0 < 10000000 ? "<col=ffffff>" + arg0 / 1000 + LocalisedText.aString239 + "</col>" : "<col=00ff80>" + arg0 / 1000000 + LocalisedText.aString49 + "</col>";
		} else {
			return "<col=ffff00>" + arg0 + "</col>";
		}
	}

The ternary return transform didn't work here - probably needs to run before we swap if/else branches.

If/else nesting in readZonePacket() could be improved.