Upgrade tokio to v1.x

[eycorsican]

Specifically this commit:

• Upgrades tokio to v1.x
• Updates all dependencies to their latest stable version
• Implements the async feature instead by tokio's AsyncFd
• Implements AsRawFd for types that need the async interface
• Removes all mio-related stuffs

[eycorsican]

The PR is tested on Linux(mipsel), iOS and macOS.

[meh]

Thanks a lot, I'm going to publish a new minor version once I get to the studio!

[eycorsican]

Thanks for the quick response! Waiting for an update on crates.io