Raft version 0.7.0

This is a major release and contains backwards incompatible changes.

Changes

• Log compaction is natively supported (3ee2c46)

Bugfixes

• The log API is fuzz tested. Just run: make fuzzer_tests. Several edge cases have been identified and fixed. The bugs were mostly related to log wrapping. (f0a2279, b912ff5)
• Fixed a rare chance of prevLogIdx < commit index breaking operations (396f7b7)