Extra JIT features

[gfwilliams]

• [x] a && b/a || b

Discussed at https://forum.espruino.com/conversations/382898/#comment16823779

It's not a bug, it's just not implemented yet. Because && is a short-circuiting operator it's not quite as simple as doing & with booleans, but it shouldn't be a huge problem (it's just the 'if' code).

• [x] array creation a = [1,2,3]

This one shouldn't be too hard, and is very useful when trying to do stuff like draw polylines

• [x] object creation a = { b : 42 }

Again, pretty useful especially when calling some built-in functions. Probably not that hard either.

[fanoush]

also array index access

>(function(){"jit";var i=0,a=Uint8Array(1);a[0]=1;return a[i];})();
Uncaught Error: Field or method "i" does not already exist, and can't create it on Uint8Array
 at line 1 col 65
...y(1);a[0]=1;return a[i];})();

workaround is using a[i.ToString()]

[gfwilliams]

Thanks @fanoush - just fixed that too