Add YangTextSchemaContextResolver feature support
YangTextSchemaContextResolver does not provide a facility to control the
set of supported features. Add
YangTextSchemaContextResolver.registeredFeatures() and a specialized
Set<QName> implementation to provide backwards-compatible way of
specifying features.
The specialized implementation does not completely conform to
Set.equals()/Set.hashCode() specification and we therefore need to dance
a bit around it.
JIRA: YANGTOOLS-1463
Change-Id: I443d42a6859ce97f238117fabdb7bbdd42488ee5
Signed-off-by: matus.matok <matus.matok@pantheon.tech>
Signed-off-by: Robert Varga <robert.varga@pantheon.tech>