Refactored configuration. Fixed tileentity skip tick feature. Fixes #1432

* Refactored configuration classes to support multiple config files.

* Moved tileentity config out of cauldron.yml to its own file due to the
  amount of tileentities that can be generated by mods. The new file can
  be found in the root directory called "tileentities.yml".
  - added new skip-tileentity-ticks setting to disable TE tick skips.
    Useful for bug tracking.

* Added config debug options for tileentities which are now
  disabled by default.

* Removed Spigot's guardEntityList.