default values containing prefixes are not directly recognized by LD-R

[mathib]

In the case of a new property value, where the reactor config has a 'defaultValue' of 'ex:someValue' and 'prefixBasedInput' is active for that property, LD-R doesn't recognize that 'ex' is a prefix, unless the user starts to edit the default value. This comes because the app looks for prefixes only if the ObjectIEditor component is active. If the default value was equal to 'http://example.org/someValue', the first part is correctly recognized by LD-R as the prefix 'ex'.

It would be easier if it's also possible to add prefixes in default values in configs. I think that it should by default look for a prefix in the list (prefixes.js). If it doesn't exist, it treats the input as a literal.