[Forms] Get date-time as UNIX timestamp

Get date-time as a UNIX timestamp (in milliseconds
since start of 1970) add the model level for date-time
controls. WTD-530.

platform/forms/res/templates/controls/datetime.html

@@ -23,6 +23,10 @@
                 <input type='text'
                        name='hour'
                        maxlength='2'
+                       min='0'
+                       max='23'
+                       integer
+                       ng-pattern='/\d+/'
                        ng-model="datetime.hour"
                        ng-required='true'/>
             </span>
@@ -30,6 +34,10 @@
                 <input type='text'
                        name='min'
                        maxlength='2'
+                       min='0'
+                       max='59'
+                       integer
+                       ng-pattern='/\d+/'
                        ng-model="datetime.min"
                        ng-required='true'/>
             </span>
@@ -37,6 +45,10 @@
                 <input type='text'
                        name='sec'
                        maxlength='2'
+                       min='0'
+                       max='59'
+                       integer
+                       ng-pattern='/\d+/'
                        ng-model="datetime.sec"
                        ng-required='true'/>
             </span>