v0.1.4

All dependencies relative to hash function implementation are now optional, dynamically imported only when the hash functions using them are used for the first time. Running pip install --upgrade multiformats will not install any of them, but they can be all installed by running pip install --upgrade multiformats[full]. In particular, this closes #4.

Hash function implementations are loaded and registered transparently on first use, to reduce memory footprint and module loading times. Analogously, a number of multibases are created and registered transparently on first use.

All hash functions with a readily available, well-supported existing Python implementation are now supported.

Finally, closes #3.