Incompatible with Mithril 0.2.2-rc1

[barneycarroll]

Mithril 0.2.2-rc1 changes m() signature forking logic, which constitutes a breaking change for Exitable.

• [x] Mandate a fixed Mithril 0.2.0 dependency so that only users with a reliable Mithril API can install Exitable
• [x] Pester Isiah & Leo about their release strategy to avoid worrying about this problem for ever
  • [ ] Actually get some kind of a release strategy out of them to inform future dependency strategy
• [x] Make Exitable 0.2.2-rc1 compatible
• [ ] Keep an eye out for reversions in a future rc / patch

[barneycarroll]

The 0.2.2-rc1 compatibility issue is this: Mithril now does extra signature sniffing in m and hands over to m.component if the first argument is statically inferable as a component.

[barneycarroll]

Mithril 0.2.0 v Mithril 0.2.2-rc1