docs(macTime, macDatepicker): Updated docs with how to clear directives

docs/directives/datepicker.md

@@ -15,6 +15,7 @@ The id of the text input field
 **mac-datepicker-model**  
 Type: `String`  
 The model to store the selected date  
+Clearing model by setting it to null or '' will clear the input field  
 
 **mac-datepicker-on-select**  
 Type: `Function`  

docs/directives/time.md

@@ -6,7 +6,8 @@ A directive for creating a time input field
 ### Parameters
 **mac-time-model**  
 Type: `String`  
-Model to bind input to  
+Assignable angular expression to data-bind to  
+Clearing model by setting it to null or '' will set model back to default value  
 
 **mac-time-placeholder**  
 Type: `String`  

docs/html/directives/datepicker.html

@@ -7,7 +7,7 @@ <h3>Dependencies</h3>
 </ul>
 <h3>Parameters</h3>
 <p><strong>mac-datepicker-id</strong><br>Type: <code>String</code><br>The id of the text input field  </p>
-<p><strong>mac-datepicker-model</strong><br>Type: <code>String</code><br>The model to store the selected date  </p>
+<p><strong>mac-datepicker-model</strong><br>Type: <code>String</code><br>The model to store the selected date<br>Clearing model by setting it to null or &#39;&#39; will clear the input field  </p>
 <p><strong>mac-datepicker-on-select</strong><br>Type: <code>Function</code><br>Function called before setting the value to the model<br>- <code>date</code> - {String} Selected date from the datepicker<br>- <code>instance</code> - {Object} Datepicker instance  </p>
 <p><strong>mac-datepicker-on-close</strong><br>Type: <code>String</code><br>Function called before closing datepicker<br>- <code>date</code> - {String} Selected date from the datepicker<br>- <code>instance</code> - {Object} Datepicker instance  </p>
 <p><strong>mac-datepicker-append-text</strong><br>Type: <code>String</code><br>The text to display after each date field  </p>

docs/html/directives/time.html

@@ -1,7 +1,7 @@
 <h1>Time</h1>
 <p>A directive for creating a time input field  </p>
 <h3>Parameters</h3>
-<p><strong>mac-time-model</strong><br>Type: <code>String</code><br>Model to bind input to  </p>
+<p><strong>mac-time-model</strong><br>Type: <code>String</code><br>Assignable angular expression to data-bind to<br>Clearing model by setting it to null or &#39;&#39; will set model back to default value  </p>
 <p><strong>mac-time-placeholder</strong><br>Type: <code>String</code><br>Placeholder text of the text input (default --:--)  </p>
 <p><strong>mac-time-disabled</strong><br>Type: <code>String</code><br>Enable or disable time input  </p>
 <p><strong>mac-time-default</strong><br>Type: <code>String</code><br>If model is undefined, use this as the starting value (default 12:00 PM)  </p>