Dynamic lights, chairs now sittable, door sounds

Also bug fixes, flight sound no longer interferes with materialisation
sounds, an experimental time rotor model added, to be removed and
replaced in a later update though - was just a test. Interior model
updated, fixed the back of the chairs having the same texture as the
front. Idle sounds now terminate when tardis is dead, dynamic light
turns red when cloister bell activates, added internal ways to reverse
tardis explosion, allowing capability for repairs in the future, added
an ENT:AddHP function that compliments this, also ENT:UnExplode - a very
inventive name.