Added note form field

Tracker item: http://joomlacode.org/gf/project/joomla/tracker/?action=TrackerItemEdit&tracker_item_id=30298

This adds a form field which you can use in the xml files for extensions.
This form field makes it possible (and easy) to create titles, texts, descriptions and even alert boxes.

This makes it very easy to bring order in the settings for extensions, by separating them with useful titles. Or adding descriptions for certain settings (without having to rely on the tooltips). Or adding any other text you want.

The syntax is pretty straight-forward:
```<field name="..." type="note" label="..." description="..." class="..." close="..." />```

So just to go through the attributes:
* **name**: contains the name of the field (like with any other field tag)
* **type**: the type of the field, which is: note
* **label**: the title of the note (uses JText) (optional if using description)
* **description**: the description/text of the note (uses JText) (optional if using label)
* **heading**: the type of heading element to use for the label (optional) (default: h4)
* **class**: a class name (or class names), like alert (see further for examples) (optional)
* **close**: a value of 'true' (for alerts) or the value for the data-dismiss of the bootstrap close icon (optional)

#### Test instructions:
To test, add these fields to the settings part of an xml file of some extension, like a module. Then go to that extensions settings in the admin and view the result of the note fields.

I have filled the label and description values with Lorem Ipsum text. But in real usage this would of course be actual language stings. So you can replace that with any language strings you wish to test with, like:
```
label="JFIELD_ALT_LAYOUT_LABEL" description="JFIELD_ALT_MODULE_LAYOUT_DESC"
```

In below examples I have placed a dummy text field (with label 'Some Other Option') between each note field, so you can see where the note field starts and ends. And can also see the spacing in relation to 'normal' fields.

###### Title and or Description
So with this note field you can either use the title or the description or both.
```
<field name="opt10" type="text" label="Some Other Option" />
<field name="note11" type="note" label="Lorem ipsum dolor sit amet" />
<field name="opt11" type="text" label="Some Other Option" />
<field name="note12" type="note" description="Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat." />
<field name="opt12" type="text" label="Some Other Option" />
<field name="note13" type="note" label="Lorem ipsum dolor sit amet" description="Consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat." />
<field name="opt13" type="text" label="Some Other Option" />
```
![note-1](https://f.cloud.github.com/assets/744259/266142/1f6f9b4a-8dd3-11e2-9d86-facaefc854a3.png)

###### Classes (Alerts)
You can add classes to the note. This way you can make (bootstrap) alerts very easily. But also any other styling via class names you want (like a 'well').
```
<field name="opt20" type="text" label="Some Other Option" />
<field name="note21" type="note" class="alert" label="Lorem ipsum dolor sit amet" description="Consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat." />
<field name="opt21" type="text" label="Some Other Option" />
<field name="note22" type="note" class="alert alert-info" label="Lorem ipsum dolor sit amet" description="Consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat." />
<field name="opt22" type="text" label="Some Other Option" />
<field name="note23" type="note" class="alert alert-success" label="Lorem ipsum dolor sit amet" description="Consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat." />
<field name="opt23" type="text" label="Some Other Option" />
<field name="note24" type="note" class="alert alert-error" label="Lorem ipsum dolor sit amet" description="Consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat." />
<field name="opt24" type="text" label="Some Other Option" />
```
![note-2](https://f.cloud.github.com/assets/744259/266143/61d63ec6-8dd3-11e2-9d24-f530d5f42a78.png)

###### Close button
You can add a close button to the alerts by adding the close="true" attribute to the tag.
If you use a different class than the alert, use the required value for the data-dismiss of the bootstrap close icon instead of the value "true".
But here is the code to test the close icon on an alert.
```
<field name="opt30" type="text" label="Some Other Option" />
<field name="note31" type="note" class="alert" close="true" label="Lorem ipsum dolor sit amet" description="Consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat." />
<field name="opt31" type="text" label="Some Other Option" />
```
![note-3](https://f.cloud.github.com/assets/744259/266146/bf42dd62-8dd3-11e2-8d8f-791fbaf8b0a0.png)