9001: Create content

{
   "tags": [ "tag1", "tag2" ],                 // required - at least one tag must be present.
                                               //    Tags must be url-safe, with this RegEx:
                                               //    [a-zA-Z]+[a-zA-Z0-9-_]*
   "contentType": "text/html",                 // optional - defaults to "text/html"
   "content": "base64 encoded content string", // required
   "value": 6.8,                               // optional - decimal
   "activeFrom": "2014-01-01T01:00Z",          // optional - ISO UTC date
   "activeTo": "2014-03-25T23:00Z"             // optional - ISO UTC date
}

{
   "contentID": 4567
}