Moved field type enums to API types header.
Merge pull request #15 from WrinklyNinja/move-fieldtypes

Moved field type enums to API types header.
User facing API type change: FORMID -> cb_formid_t
User facing API type change: collection_t -> cb_collection_t
User facing API type change: mod_t -> cb_mod_t
User facing API type change: record_t -> cb_record_t
User facing API changes: add `cb_` prefix to function names

* Breaks backwards compatibility, anyone using CBash.dll would need to
  rebuild/relink with the new function names.
* Option config setting, if you define `CBASH_SHORT_NAMES`, macro versions
  of the functions with the original names will be provided as aliases to the
  new function names.