* I don't care about observable stores
* enforce explicit initializations
* cleaner code for the stdlib
* stdlib: use explicit initializations
* make tests green
* algorithm.nim: set result explicitly
* remove out parameters and bring the PR into a mergable state
* updated the changelog
* added bit operations based on bit slices, clarified documentation, made non-mutating versions of mask ops
* Added since annotations, some runnable examples
* Added mask()/masked() functions, changed internal workings of mask ops to use new bit* funcs
* Changelog updated for new bitops improvements
* Reorganization, added runnable examples
* Documentation adjustments
* Add incltrl for since annotation
* Fix masked() impl
* Fix mask() return type
* Don't call toUnsigned on already unsigned types
* Remove improper `var T` for flipMasked()
* Fix return types for flipMasked()
* Slight syntactic cleanup for *masked ops
* Added tests for bitslice operations, new mask() operation, non-mutating mask ops
* Fix setmasked() var T issue
* More comprehensive tests
* Fix runnable example for bitsliced()
* Fix runnable example for mask()
