Bump to 0.5.0

Summary:
The minimal set is now used by default.

To switch to the default Diesel set, use the following in Cargo.toml:
limiting-factor = { version="^0.5.0", features = ["full"] }

Reviewers: dereckson

Reviewed By: dereckson

Differential Revision: https://devcentral.nasqueron.org/D1887