import: let --exact 'work' with --no-commit (issue4376)

obsolete: use C code for headrevs calculation Previously, if there were filtered revs the repository could not use the C fast path for computing the head revs in the changelog. This slowed down many operations in large repositories. This adds the ability to filter revs to the C fast path. This speeds up histedit on repositories with filtered revs by 30% (13s to 9s). This could be improved further by sorting the filtered revs and walking the sorted list while we walk the changelog, but even this initial version that just calls __contains__ is still massively faster. The new C api is compatible for both new and old python clients, and the new python client can call both new and old C apis.

revset: simplify orderedlazyset creation in spanset method We can simply use the `self.isascending` value instead of more complex if/else clause. This get the code simpler. Benchmarks show no performances harmed in the process.

revset: use spanset.isdescending in multiple simple places We call the method directly instead of duplicating checks. Benchmarks show no performances harmed in the process.

revset: wider definition of ascending and descending for spanset Before this patches, empty spanset were seen as neither ascending nor descending. This is mathematically wrong and create some edges case. We put `isascending` and `isdescending` back on track so we can use them to simplify some of the spanset code. Benchmarks show no performances harmed in the process.

annotate: port to generic templater enabled by hidden -T option If the selected formatter is other than plainformatter, raw data are passed to the formatter. In this case, it isn't necessary (and not possible) to calculate column widths. Field names are substituted to be the same as "log" command. There are a few limitations: - "binary file" message is not included in formatted output. - no data structure for multiple files. all lines are packed to single list.

annotate: split functions to get data without applying text formatting This prepares for porting to generic templater API, where raw data should be passed to the formatter. makefunc() is necessary to build closure in list comprehension.

annotate: remove unused variable in calculation of column widths

annotate: build format string separately from annotation data This prepares for porting to generic templater API. Note that we cannot use '%*s' to pad white spaces because it doesn't take into account character widths, as described in 4f5a6df2af92.

formatter: convert float value to json It will be used to encode ctx.date().