Parsing and emitting for clear method for maps and lists; still need to add backend code to actually support clear operation and to add test code for it.
Added clear methods for maps and lists.
Added test code to ensure that clearing maps+lists works.
Expanded interrupted atomically tests for nested atomically-s.
Checking that will retry event even if backed out from multiple levels
of atomically.
Added alias statement: can replace type with string.
Removed previous alias construct that's attached to struct declaration.  Instead use alias at top of file.
Added alias statements for endpoint types.
Added endpoint as a type.  Must add library and emit code to support endpoints.