Caluma

Fix
* Validate inexisting references in calc questions ([`f4de05a`](https://github.com/projectcaluma/caluma/commit/f4de05a2e1506c15861a11a3274846d06949d7ab))
* Separate extractor for mapby arguments ([`34c6d2b`](https://github.com/projectcaluma/caluma/commit/34c6d2b370a2415517127c5f5e3e48238a00ab7c))

Feature
* Calculated float question ([`6a7c7ca`](https://github.com/projectcaluma/caluma/commit/6a7c7ca631a8aca66827124512c02c3e54cc5173))

Fix
* __str__() should return string ([`df5ba3b`](https://github.com/projectcaluma/caluma/commit/df5ba3b36547492f45c02cab1904a73efa792a80))
* Use mapby args if literal, fix calculated test ([`cb49617`](https://github.com/projectcaluma/caluma/commit/cb496173b48aa282af07a01e6f91b1e314a065a8))
* Support validation of nested table answers ([`7937220`](https://github.com/projectcaluma/caluma/commit/7937220b8872faadadb0f13c6e7ca004afcf1f02))
* Use "mapby" arg if subject is answer transform ([`3a595a8`](https://github.com/projectcaluma/caluma/commit/3a595a829a6a8ab1e1499999c792a7a30bb00458))

Fix
* Fix validation of table questions ([`6e1cf82`](https://github.com/projectcaluma/caluma/commit/6e1cf826e84b0dc6c866ba801b1c213bc85049d4))

Feature
* Support multiple choice and improve choice search ([`456bf08`](https://github.com/projectcaluma/caluma/commit/456bf0805329f7c6170dcedea37545351acc7a4a))

Fix
* Validate empty table answers correctly ([`8b00505`](https://github.com/projectcaluma/caluma/commit/8b0050532fe16f04e9ac7bf02fbe80a402645bad))

Fix
* Fix custom validation for save answer mutations ([`5e91341`](https://github.com/projectcaluma/caluma/commit/5e91341bad29751436ca94c8faac879277e7cb6c))

Feature
* Introduce API for managing default_answers ([`995138a`](https://github.com/projectcaluma/caluma/commit/995138a735ab736abe771c2b0574d72bf55fe286))
* Pass user to copy method on answer and doc ([`38941b0`](https://github.com/projectcaluma/caluma/commit/38941b0e6a336d2578b5786fd1c641565bd788a7))

Fix
* Fix empty answers ([`fc6300b`](https://github.com/projectcaluma/caluma/commit/fc6300bd578faee85fd8ecc1b1109cd1976d3bfa))