[mr2934] use costructor/destructor in ViewPoint instead of manual clearing. some safety and speedup.
[mr2935] Drop outdate codes and revert to YTDB.
[mr2936] Implement TARGET_RANDOM_UNIT_CHAIN_IN_AREA

Also unify TARGET_RANDOM_xxx_CHAIN_IN_AREA into one code.

Note: removed check for SPELL_ATTR_EX6_IGNORE_CCED_TARGETS, not have any spells with this attribute and such targets (checked up to 5.1.0).
[mr2937] Implement TARGET_FRIENDLY_FRONTAL_CONE
[mr2938] Implement TARGET_SINGLE_ENEMY_2

Only one spell 45105 has this target type. hehe
[mr2939] use guids instead of pointers in DungeonPersistentState v0.2. must be much more safe. related to #1406 and some more old. testing.
SD2 update
Merge branch 'master' into testing
Revert "Reorganize R2 thread bucket manager v0.5.3, add templated class for possibility continue parallilize tasks. testing (no any changes must be currently). need check compile under win. Ready for testing."

This reverts commit a07ca757a40a0c055710a465714d1e94df34d8bd.
Reorganize R2 thread bucket manager v0.5.4, add templated class for possibility continue parallilize tasks. testing (no any changes must be currently). need check compile under win. Ready for testing.
related to #1402 and some more old.
- also some rework in VMSS (to be continued)
- statistic passed to template (hooks)