cat-select should allow creation of none existing endpoints (suggestion)

[mkurz000]

Reason:

• If you are using a UI which is quite dynamically composed by aggregation of multiple HTML templates (Some templates could even be provided by plugins).
• If these templates contain "cat-select" directives the definition of the "endpoint" would require an additional block of javascript code (Code-Behind).

Possible solutions:

• Add a "autocreate" option to cat-select, which will create none existing endponts.
• Add an attribute directive, which creates none existing endpoints.