Introduce RDKit.js

[Acylation]

Add RDKit.js a new render core.

Fixes #20 & #46

Features

non-Tetrahedron chiralty

SMILES: NC(Br)=[C@]=C(O)C

Radicals

SMILES: CC[CH]CC

Limitations

• The color of radical symbol is always black. So in dark mode it could become invisible. Please use light themes temporarily.
• Reactions can't not be styled with themes like molecules. They will all be rendered in light theme and with a white background.
• RDKit uses cut-off on heteroatom bonds, while Smiles Drawer uses gradients.