v0.13.0

Major refactoring, adding new features and removing features outside the scope
of the crate.

Added

• Parallel iterators enabled by the parallel feature.
• #![no_std] support by disabling the std feature.
• WorldBuilder for creating worlds using the builder pattern.

Changed

• All query operations are now performed via the World::query_one and
  World::query_all.

Removed

• ResourceStorage: outside the scope of the crate.