Update l4d_tank_control_eq

- Updated syntax and removed some redundant/unused code/checks.
- Improved consistency in code, naming and positioning.
- If tankcontrol_print_all is set to 1 the plugin will now also print who's becoming the Tank whenever a Survivor uses the Tank_Cmd (instead of just at the start)
- Replaced Caster related code with Spectator checks (removed caster_system checks).
- Spectators now also see who's becoming the Tank when using the Tank_Cmd.
- Spectators now also get a chat print for when the Tank's Rage Meter is refilled.