v3.10.0

=== Fixes ===
* pkg-config files will take `DESTDIR` env var into account when selecting install destination (catchorg#3006, catchorg#3019)
* Changed `filter` to store the provided predicate by value (catchorg#3002, catchorg#3005)
  * This is done to avoid dangling-by-default behaviour when `filter` is used inside `GENERATE_COPY`/`GENERATE_REF`.

=== Improvements ===
* Escaping XML and JSON output is faster when the strings do not need escaping.
  * The improvement starts at about 3x throughput, up to 10x for long strings.
* Message macros (`INFO`, `CAPTURE`, `WARN`, `SUCCEED`, etc) are now thread safe.