by tirsales: Fixed error in bookingsapi_booking_save (insert/update swaped)
  Added call to bookingsapi_record_status_change when saving a booking

by tirsales: Added bookingsapi_numeric_record_status and
  bookingsapi_numeric_record_types

  present.

by tirsales: Fixed bug in bookingsapi_record_types
  (now returns string on int param). Also fixed in bookingsapi_form.inc
by tirsales: Fixed bug in bookingsapi_record_status
  (now returns string on int param). Also fixed in bookingsapi_form.inc

Primarily fixes critical issues brought up Views RC4, along with existing bugs and issues.

Also includes database schema changes: removes 'ical_' from 'ical_rrule' and 'ical_rrule_until'.

Many thanks, dwees!

Added record status custom handlers, fixed function naming consistency, and added a custom filter handler for start and end fields for compatibility with the DATETIME columns used in the table.

Added 'unconfirmed' and 'denied' status codes, and a function for changing just the status code of a record.

- Renamed '_S' constants and ENUM values to '_S', for 'Strict'. Probably more intuitive than R for 'Rigid'.
- bookingsapi_conflict_check() can now optionally check for potential + certain conflicts, in addition to certain conflicts only.

- Removed record form's #submit as it was unnecessarily causing #validation to be ignored.
- BOOKINGSAPI_UNA_R -> BOOKINGSAPI_UNA_S (S for Strict, renaming)

Marked essential form fields as 'required'.

Added availability deletion function (untested).
Split off RRULE exception and recurrence calculation into a separate helper function.

Form fixes. Moved emptying of a non-recurring RRULE to form validation. Blocked RRULES that don't have an UNTIL.

Added new status and type code helper functions for translating both ways between code and name, geared towards those columns later becoming ENUM; should also work with regular int columns in the meantime.

Changes to reflect the addition of the third table, bookings_schedules, which all instances of every record.

Added functions for deleting records, and deleting instances of records while preserving EXDATE integrity. Untested.

In conflict checking, resources with a parent will inherit all bookings and unavailabilities made to that parent. This can be used such that bookable rooms all have their parent as 'the entire building', and bookings/availability information for 'the entire building' will be inherited by the rooms.

Helper function for updating the `created` and `modified` removed: later this can be taken care of at the database level with ON UPDATE CURRENT_TIMESTAMP, along with a trigger.

And miscellanous fixes and expansion.

MySQL and MyISAM-specific tweaks and optimizations will come later; the new table will be fixed-length.

Test file for records CRUD and conflict detection. Many things in it tests functions not yet created.

Split API forms into separate include file.

CRU operations for bookings and availabilities implemented, but not deletes.

Nomenclature: 'bookables' are now 'resources'.

Database: Added new indexes, ical_rrule_until for fast searching through repeat end dates, and repeat_parent for managing records that are just instances of a repeat (not yet implemented, just decided this was the best way to go).

The broken conflict detection functions in this commit contradict with the new strategy of creating all instances of a repeat at once. Just ignore it for now.

Revised API functions for CRUD operations on bookable resources. Test file updated accordingly. Basic form templates are available for implementing modules to use, through _form functions. API will not accept or validate forms - up to implementation to do so.
Functions for booking and availability CRUD largely untouched for now.