Parse CSS classes more acurrately with AST parser

[constgen]

Use css-tree parser to target only class selectors in CSS. This fixes a lot of problems ones and forever

• No more false positives in decimal property values. They was detected as classes because of .
• Allow absent trailing semicolon in last rule in declaration. This have to work as it is valid by CSS spec
• Better code base flexibility for future features, e.g.: animation names scoping, etc.

Resolves #4

@nairinarinyan please build from TypeScript locally and try to make it run successfully. I am not a "friend" of TypeScript and tested it only in pure JavaScript directly in node_modules

[constgen]

@nairinarinyan can you merge this please? It resolves many issues in CSS corruption produced by this plugin.