Fix various bugs and add Meta initializer

What's Changed

• Make GMM documentation more visible, fix bug in M step of EM algorithm by @geoff-davis in #144
• Feature/initializers as literals by @michalk8 in #148
• Fix fused_penalty and scale_cost in LRGW by @michalk8 in #147
• Add dtype property by @michalk8 in #150
• Meta OT Initializer by @bamos in #145
• fix power=1.0 using abs on cost values when needed by @marcocuturi in #153

New Contributors

• @geoff-davis made their first contribution in #144

Full Changelog: 0.2.9...0.2.10