Release of 1.0.4

- 7da6110d3d9f251803d17ea7a6e8405da5d74a27: Merge pull request #2237 from benjchristensen/publish-ring-buffer-usage
- e39599cc4fc01864d6aa1297b85c414d53bc97a2: Make Publish Operator Release RingBuffer
- 4a0864423d68a6862ad38173d55a9f4d239689d3: Merge pull request #2052 from davidmoten/make-class-static
- 2f821d855556ed4c23cad9df7bb19294d1491cba: Merge pull request #2156 from zsxwing/map-swallow-fatal-exceptions
- a683fccd1e2ee5b7cfabbda473a885f2521ac26b: enable faster travis builds
- 3563021690b04d18c2419d8b2c2f1cf8b5065be4: Fix the issue that map may swallow fatal exceptions
- 9cae73992449329a11068c5f50cad64963f70bc0: Merge pull request #2053 from akarnokd/ReplaySubjectBoundedFix1218
- 1a068ddfd2b9fbadcadb2b49ef20fc93782edc3a: Fixed wrong subject use in test.
- 093bbeb69b77b14b5db39f7f32a4637cf75ae57a: OperatorDoOnRequest.ParentSubscriber should be static class
- 7c408f47176d5b1b3a9c95ce1f5664c6839db2dc: Merge pull request #1967 from zsxwing/fix-groupby-unsubscribe
- 5c0be524b263476d714c6165a6171a35eb76a5f6: Version 1.0.3
- 31281b60e56032ba1d7c99b9411132756f9c2844: Update as per review
- 83fc06f331c448a6aeb808592245e020384ce5e5: Add a new state of `terminated` to fix the race condition of `errorEmitted`; Add more comments.
- 272a7521188e4e174e5903b688be390315d470d5: Propagate onError to all groups
- 8026b41bb21e7e7c1103d0492e890ff0093fd6c8: Fix the issue that GroupBy may not call 'unsubscribe'
