Fixed support for curies where there is only one curie.

Draft 5 claims that

   >The CURIE Syntax [W3C.NOTE-curie-20101216] MAY be used for brevity
   for these URIs.  CURIEs are established within a HAL document via a
   set of Link Objects with the relation type "curies" on the root
   Resource Object.  These links contain a URI Template with the token
   'rel', and are named via the "name" property.

My interpretation was that this is standard hal - if there is one curie, have a single object, if there are many, have an array. Currently, hal-browser only works if there is either one curie called 'curie' (draft < 4, for backwards compatibility), or multiple curies called 'curies'. This fixes that bug.