tool_build/package_compiler: made lookup interface more strict.

tool_build/package_compiler:
	removed has_resource();
	added tags_lenient option to find_resource_id();
	added parameterized find_resource_id().

tool_build/compiler_manager:
	added identity parameters to has_resource().
resource/resource_package: added null entry check to resource_metadata() & assertion message.
resource/resource_package: close_resource_stream(): corrected assertion message.
resource/resource_package: lookup metadata with resource_metadata().
resource/resource_package: replaced find_resource() with get_node().¹

1: Lookup criteria will be governed by resource_manager. It only
needs the start point for the primary identifying information of
a resource (its name).
resource/resource_manager: renamed TypedResource to TypedResourceValue for consistency.
resource/resource_manager: reworked internal lookup.

resource/resource_manager:
	replaced find_resource() with resource_metadata();
	added get_active_node() and has_resource() to search for loaded resources;
	based all active lookup on get_resource();
	reworked load_resource().
string/string: added size(), copy(), and append() definitions for Array.
resource/resource_manager: only assert handler existence where it is used.
resource/resource_manager: ensure base path is non-empty.
resource/resource_manager: added clear_handlers() and clear_resources().
app/app: added resource_manager member and base_path ctor parameter.
test/resource/manager: updated handler registration.
test/app/general: URC.¹

1: Introducting this "Update due to Recent Commit(s)" for changes
that cascade to tests, but where the test behavior doesn't actually
change.
test/.gitignore: excluded packed packages.
tool_build/compiler_manager: URC: resource_compiler.
gfx/renderer/opengl: corrected bound assertion for g_gl_buffer_data_binding.
gfx: added valid() to ResourceID.
gfx/renderer/private: corrected ID assignment order.¹

1: Ooooooops.
gfx/renderer: added type().