Update Documentation

What's Changed

• Change loss to activation by @fuzhanrahmanian in #28
• github link in docs and install in usage by @Sparkier in #36
• Updating transformations by @fuzhanrahmanian in #31
• Update regularizer by @fuzhanrahmanian in #32
• Update optimizer by @fuzhanrahmanian in #33
• Inline show notebook by @fuzhanrahmanian in #35
• Update preconditioning by @fuzhanrahmanian in #34
• add icon to readme and docs by @Sparkier in #38
• Fix mistake in _linear_decorrelate_color docs by @ProGamerGov in #39

Full Changelog: https://github.com/Sparkier/luna/commits/0.2.1