Add support for generalized aggregate groups

Aggregate groups can now be any expression. The most useful is probably a boolean expression in queries like:

* | json | p50(response_time), p90(response_time) by url, status_code >= 400

where is now out of beta and supports the full range of comparators (==, <=, !=, >=, >, <)

This release marks one of the last that changes the language. Future releases will be focused on usuability

v0.7.2

Add documentation about the where operator

v0.7.1

Update README

Add support for multi aggregates

Note: this release contains a breaking change to accommodate multi-aggregates. as clauses.

This release adds support for have multiple aggregate function in the same operator allowing for queries like:

* | json | count, p50(response_time) by status_code

Lots of moving parts in this release. Please report any issues or panics.

v0.6.3: Small bugfixes

- Fix padding when formatting aggregates
- Exit with a status code of 1 when the query is invalid

v0.6.2

Add fields operator + big performance improvement for aggregates

v0.6.1

Add fields operator

v0.6.0

Rename to agrind

v0.5.1

Performance improvements + support for `parse from` & `json from`

v0.5.0

Add support for sorting aggregates