* no_std support
* Use integer log2 when possible to estimate allocations
* Remove std features from a few dependencies
* Use libm for missing funcs in nostd environment
* Use autocfg to detect presence of i128
* Better CI test for nostd environment
* Move benchmark to a separate crate
* Make the tests pass in no_std builds
* Use thumbv7m target for nostd build test
* Add documentation about the no-std compatibility
* Make zeroize and prime features no_std-compatible
* Test each feature in nostd context
* Fix mac test to work in no_std environment
* Avoid using thread_rng in nostd tests
* Fix prime tests in nostd mode
* Fix all warnings and errors
* Only test nostd builds on nightly on travis
* Travis: Only do nostd builds on nightly
