* initial version, still a work in progress
* remove redudant or
* add chrono::DateTime and index i64
* add more tests
* fix tests
* pass DateTime by ptr
* remove println!
* document query_parser rfc 3339 date support
* added some more docs about implementation to schema.rs
* enforce DateTime is UTC, and re-export chrono
* added DateField to changelog
* fixed conflict
* use INDEXED instead of INT_INDEXED for date fields
* Split Collector into an overall Collector and a per-segment SegmentCollector. Precursor to cross-segment parallelism, and as a side benefit cleans up any per-segment fields from being Option<T> to just T.
* Attempt to add MultiCollector back
* working. Chained collector is broken though
* Fix chained collector
* Fix test
* Make Weight Send+Sync for parallelization purposes
* Expose parameters of RangeQuery for external usage
* Removed &mut self
* fixing tests
* Restored TestCollectors
* blop
* multicollector working
* chained collector working
* test broken
* fixing unit test
* blop
* blop
* Blop
* simplifying APi
* blop
* better syntax
* Simplifying top_collector
* refactoring
* blop
* Sync with master
* Added multithread search
* Collector refactoring
* Schema::builder
* CR and rustdoc
* CR comments
* blop
* Added an executor
* Sorted the segment readers in the searcher
* Update searcher.rs
* Fixed unit testst
* changed the place where we have the sort-segment-by-count heuristic
* using crossbeam::channel
* inlining
* Comments about panics propagating
* Added unit test for executor panicking
* Readded default
* Removed Default impl
* Added unit test for executor
* Add fast field for associating arbitrary bytes to a document
* Fix unused macro_use warning
* Improvements from code review
* Make BytesFastFieldWriter public
* Fix json parsing validation failure
* Add bytes fast field to CHANGELOG.md
* Fix compile errors from merge
* Support merging
* Address misc code review comments
* Fix comments from CR
- internally wrapped by an Arc, cloning aggressively is ok.
- a field in schema, redundant with metas
- read-only. Needs to be built via a SchemaBuilder.
