* Make `strict_hash` deterministic for `NAN`
* Make `strict_hash` return the same value for signed positive and negative zero. (In php, `0.0 === -0.0`, though var_export/print/var_dump output differ.)
* Fix StrictMap/StrictSet handling of NAN. Make StrictMap/StrictSet treat positive and negative zero floats as the same key, like SortedStrictSet/stable_compare.
* Add bitset source files to package.xml