DDlog v.0.32.0 with fix for serde regression.

Rust serde lib no longer re-exports std.

serde release 1.0.119 changed the public interface of the library
without incrementing the version number.  Specifically, it no longer
re-exports bits of the standard library.

DDlog v0.34.2

New features

• Support for ephemeral streams

DDlog v0.34.1

Bug fixes

• Fix linker problem on MacOS.

Improvements

• A heuristic to make type inference errors easier to understand.

Libraries

New functions in internment.dl:

```
function parse_dec_u64(s: istring): Option<bit<64>>
function parse_dec_i64(s: istring): Option<signed<64>>
```

DDlog v0.32.1 with fix for serde regression.

Rust serde lib no longer re-exports std.

serde release 1.0.119 changed the public interface of the library
without incrementing the version number.  Specifically, it no longer
re-exports bits of the standard library.

DDlog v0.34.0

[0.34.0] - Jan 11, 2021

Bug fixes

• A change in serde caused DDlog-generated Rust code to stop compiling,
  affecting all recent DDlog releases.

API changes

• Removed callback argument from HDDlog::run, ddlog_run, and Go/Java language
  bindings based on ddlog_run. This optional callback, invoked by DD workers on
  each update to an output collection complicated the API and was tricky to use
  correctly. Most importantly, it is superseded by the commit_dump_changes API.

Added

• Added the ddlog_derive crate that provides derive macros for the FromRecord,
  IntoRecord and Mutator traits
• Added the Record::positional_struct_fields() method to allow fetching positional
  fields from records
• Added the Record::get_struct_field() method to allow getting a struct record's
  field by name

DDlog v0.33.0

Optimizations

• An optimized implementation of the distinct operator may save memory and CPU
  for recursive relations.

Libraries

• Added support for regex sets to lib/regex.dl
• Added Vec::pop() function to lib/ddlog_std.dl.

Miscellaneous improvements:

• Upgrade to the latest versions of timely and differential dataflow crates.

DDlog v0.32.1

[0.32.1] - Dec 22, 2020

Optimizations

• Sped-up the compiler: eliminated several performance bottlenecks, most notably
  in the type inference algorithm. This yields a 10x speedup on large DDlog
  projects.

Bug fixes

DDlog v0.32.0

• Decompose generated Rust code into crates for faster re-compilation: #850

DDlog v0.31.0

• Windows support.

DDlog v0.30.0

• Simplified Rust API.