BUG: collection measurement date/time field issues (#83)

app/models/collection-measurement.js

@@ -3,7 +3,7 @@ import DS from 'ember-data';
 const { Model, attr, belongsTo } = DS;
 
 export default Model.extend({
-  dateMeasured: attr('string'),
+  dateMeasured: attr('ccdb-date'),
   timeMeasured: attr('string'),
   waterTempC:   attr('number'),
   airTempC:     attr('number'),

app/models/collection.js

@@ -11,7 +11,7 @@ export default Model.extend({
   collectionStartTime: attr('string-null-to-empty'),
   collectionEndDate:   attr('ccdb-date'),
   collectionEndTime:   attr('string-null-to-empty'),
-  notes:               attr('string'),
+  notes:               attr('string', { defaultValue: '' }),
 
   project:           belongsTo('project'),
   studyLocation:     belongsTo('study-location'),