* remove `@setGlobalAlign`
 * add align keyword for setting alignment on functions and
   variables.
 * loads and stores use alignment from pointer
 * memcpy, memset use alignment from pointer
 * add syntax for pointer alignment
 * slices can have volatile
 * add u2, i2 primitives
 * ignore preferred align and use abi align everywhere
 * back to only having alignOf builtin.
   preferredAlignOf is too tricky to be useful.
   See #432. Partial revert of
   e726925e802eddab53cbfd9aacbc5eefe95c356f.

See #37