v0.7.0

Another release is here 🚀🚀🚀

As usual, a bunch of optimizations as well as some work in two main fronts:

• make the crate smaller and easier to compile
• support for nested parquet reads

Thank you to all contributors (names below) for the amazing contributions!

Breaking changes:

• Simplified reading parquet #532 (jorgecarleitao)
• Change IPC FileReader to own the underlying reader #518 (blakesmith)
• Migrate to arrow_format crate #517 (jorgecarleitao)

New features:

• Added read of 2-level nested lists from parquet #548 (jorgecarleitao)
• add dictionary serialization for csv-writer #515 (ritchie46)
• Added checked_negate and wrapping_negate for PrimitiveArray #506 (yjhmelody)

Fixed bugs:

• Fixed error in reading fixed len binary from parquet #549 (jorgecarleitao)
• Fixed ffi of sliced arrays #540 (jorgecarleitao)
• Fixed s3 example #536 (jorgecarleitao)
• Fixed error in writing compressed parquet dict pages #523 (jorgecarleitao)
• Validity taken into account when writing StructArray to json #511 (VasanthakumarV)

Enhancements:

• Bumped Prost and Tonic #550 (PsiACE)
• Speedup scalar boolean operations #546 (Dandandan)
• Added fast path for validating ASCII text (~1.12-1.89x improvement on reading ASCII parquet data) #542 (Dandandan)
• Exposed missing APIs to write parquet in parallel #539 (jorgecarleitao)
• improve utf8 init validity #530 (ritchie46)
• export missing BinaryValueIter #526 (yjhmelody)

Documentation updates:

• Added more IPC documentation #534 (HagaiHargil)
• Fixed clippy and fmt #521 (ritchie46)

Testing updates:

• Added more tests for utf8 #543 (jorgecarleitao)
• Ignored RUSTSEC-2020-0071 and RUSTSEC-2020-0159 #537 (jorgecarleitao)
• Improved parquet read benches #533 (jorgecarleitao)
• Added fmt and clippy checks to CI. #522 (xudong963)