Allow localized date input and correctly transform for custom date fields
Patch allows users to manipulate custom date fields using their local format.
- Adds a library routine to the I18n extensions. The routine provides for the parsing of a user entered date into a Date object.
- The custom value model has been upated to correctly account for the user's date setting (if available). If not, defaults to YYYY-MM-DD.
This allows users to enter their dates in their localized format (as defined by setting.date_format), and have it correctly transformed to YYYY-MM-DD. If the localized setting is not available, falls back to YYYY-MM-DD for input.
This partially fixes defect #668 as it applies to custom fields. This was a major pain point for our users, so hopefully will solve a lot of problems experienced elsewhere.