Schema and options files can't be find by app

[teosibileau]

if no STATIC_ROOT and JSONFORMS_SCHEMA_DIR settings are set then JSONSchemaField.load can't find schema in apps static folder.

django.contrib.staticfiles.finders could be use instead.

[teosibileau]

working on getting those tests green

[harrywhite4]

Would definitely be better to use staticfiles finders. Will pull that in when it's ready