Testing : precheckin --full --strict-errors
Reviewer: Fare (please)

JTB impact: No
Ops impact: No

Change to config                        : No
Change to XML schema                    : No
Change to DB schema                     : No
Change to transport (timeouts, headers) : No
Any change (or new use) of OAQs         : No
Change to inter-component transactions  : No
Depends on any other checkin / bug      : No

Tests that will verify:

The CL-Protobufs tests

Description:

Add type aliases to CL-Protobufs. It's a Lisp-only
feature that allows you define a new Protobufs type in
terms of a Lisp type, a serializer and a deserializer.
 - Add a new model class, 'protobuf-type-alias'.
 - Extend schemas and messages so that they can hold
   a set of type aliases; add 'find-type-alias'.
 - Add 'define-type-alias'.
 - Factor out 'lisp-type-to-protobuf-type' from
   'clos-type-to-protobuf-type', I need it for the
   'define-type-alias' macro.
 - Fix the schema printer to print 'define-type-alias'
   for .lisp schemas, and to add a comment describing
   the type alias in .proto schemas.
 - Extend the wire format (de)serializer to know
   about type aliases; it just (de)serializes the
   Lisp type as the Protobufs primitive type using
   the provided (de)serializer functions. There's
   zero cost to this if you don't use aliases.
 - Update the optimized serialization generation.
 - Similarly extend the text format (de)serializer
   to know about type aliases.
 - Change an example to use a type alias for 'date'.
 - Update the documentation.



git-svn-id: http://svn.internal.itasoftware.com/svn/ita/trunk/qres/lisp/libs/cl-protobufs@559861 f8382938-511b-0410-9cdd-bb47b084005c