Monster skill use behavior, ranges, position lag fixes
- Updated monster skill use behavior so monsters use skills the same way and at the same rhythm as official servers (bugreport:009326), the changes include:
 * Unified the "monster can't move by default" and the "monster trapped" code as it really should behave exactly the same
 * Fixed a bug that caused the "monster skill use" routine to be called 20 times more often than it should in some situations
 * When a monster attacks you and you run away from it, the monster will now check if it has a ranged skill on "attack" state before switching to chase state
 * Monsters will now always do a normal attack before using "attack" state skills
 * Fixed a bug that caused monsters to switch to idle mode and never use their chase skills when they get hit continuously
 * Changed default for skillrange_from_weapon from 30 (all but player) to 0 (none); monsters will now use all skills at the skill range and not at their own attack range, if they get tanked from farther away than skill range, they won't use these skills
- Updated ranges to work as on official servers (bugreport:009326), the changes include:
 * Implemented new functions "check_distance_client" and "distance_client", that instead of the server-sided square range system use the circular one that the client uses; these functions should be used for units that send their commands via the client (players mostly)
 * Applied the new distance algorithm to some player-specific range checks, players will now have a circular attack range that reflects their attack range on the client; this makes it impossible to hack the client for more diagonal range
 * Removed the arbitrary +1 range bonus at range checks; as monsters now react fluently, they won't need it anymore, that means a monster with for example 4 attack range will now only attack targets within a 9x9 area around it, the moment you step out of this area, the attacks will stop (if the monster can move it will follow you); as for players, the extra cell attack range when on a linear line to the target now is integrated into the distance algorithm, that means a player with attack range 4 can attack from 5 cells away when directly on line with a monster, but no longer diagonally as range is circular for players now
 * Implemented a new "step action" feature to reflect official chase range behavior; when an attack or skill is used inside the attack range, it will act exactly as now, the skill is used once the signal from the client was received; however, if an attack or skill is used outside the attack range, the player should move into the chase area which is 1 cell inside the attack range border; the client actually sends us where to use the attack / skill from, but previously we just dropped that information the moment an attack request came; now instead of stopping the player instantly on an attack request, the player will continue moving to the target cell and then automatically use the command received earlier (it will be remembered); this change was absolutely necessary as the client sends the attack request slightly before attack range is reached, execution on official servers only takes place on every full cell moved; the new system copies this behavior
- Implemented an improved hit-lock system (bugreport:007460), the changes include:
 * MVPs are no longer immune to being stopped by a hit unless they used Endure
 * When hitting any unit, it will stop for its "dMotion" interval, exactly at the end of "dMotion" it will continue walking (official behavior); this helps getting more "move" packets to be displayed
 * The unit that was hit will be immune to being stopped for another "dMotion" interval, this allows to slow down any units by hitting them frequently, but makes it almost impossible to completely stop them forever (depends a lot of ASPD and dMotion value); this does not affect special hit-lock properties (some skills and events should set delay anyway)
 * The unit that was hit will no longer be "pulled" to the next cell; this caused a lot of position lag, it should be much better now
- Fixed Sightrasher missing its variable cast time in Renewal