v1.0.0-beta

This is a remake of an initial version.
Written with async/await, optimized.
Files are now resolved and concatenated in a single-traverse.
Also, prints out imports tree and indicates if an import is not found.

Fixes:

• Doesn't load partials correctly when imported by omitting initial _ (#5)
• 1.0.0 rewrite (#6)
• Optimize with single-traverse (#7)