Struct packing rules should result to a size of 16.

[stolk]

So, we really expect the struct size to be 16 here.

To be safe, I used <= 16 in case Visual C++ does something strange.

For struct, other than the alignment need for each individual member, the size of whole struct itself will be aligned to a size divisible by strictest alignment requirement of any of its members, by padding at end.

Fixes issue #216

[aardappel]

Apologies I pre-empted you.

Decided that if most compilers were going to add padding, might as well use that padding for larger fields, and get rid of all the (apparently not portable) packing trickery: https://github.com/aardappel/lobster/commit/3b2deb5289b87a8f1a67ef01ac0c448549b558b9