implem life steal modifier, update enemy and hero prefabs, moved enemy oncollosionenter2d to health script

added reset platform to level2, removed mesh renderer on level1 reset platform, added shop to level1, added colliders to level2, made transition from level1 flag to level2

added ice tile assets for level 2 and buildings tile assts for level 3. added scene level2 with most of the ground completed

code for gun rotation added which called method UpdateWeaponRotation (rot); which is not yet implemented

added item detection radar. Added rigidbodies to items. Added item attributes and modifier string getters for UI. Added RNG to number of modifiers. Added rate of fire to weapons