Fixed bug in template replacement, added test. Multiple statements in a single Content element are
now evaluated correctly.
Work in progress on replacing builtin types with dynamic types plus mixins.
Added missing mixin files from previous commit.
First working prototype of overridden builtin classes to support linking with dynamic schema types.
Implemented dynamic property registration for builtin types.
Merge branch 'develop' into remove_builtin_types

Conflicts:
	structr-core/src/main/java/org/structr/schema/SchemaService.java