v0.7.3

Change Log:

• Various tests, fixes, and improvements to type safety

Pull Requests

• Fix deadlock in mempool for synchronous apps - Fix race condition; Refactor out txCache #290
• Type safe FireEvent - Type safe fire event #291 - thanks @ethanfrey
• Replay handles non-empty blocks, add more tests - Replay fixes #296
• Fix race condition in HeightVoteSet- consensus: hvs.StringIndented() was missing a lock. addresses #284 #298
• Cleanup some docs - remove INSTALL dir, add INSTALL.md, update DOCKER #297