Update CSS with classes and remove dynamic styles

[alexhgreen07]

I would like to remove the dynamic styles generated when 'pivot_display()' is called. Also the <h2> tags should be changed to a CSS class. The list of change items is below:

• Replace <h2> tags with <span class="pivot_header2"> tags.
• Replace dynamic styles with CSS classes 'pivot_field':

.pivot_field
{
        float: none; 
        width: 300px; 
        margin-left: 20px;
}

The new code will look like:

<div class="pivot_field">
<span class="pivot_header2">Filter Fields</span>
<div id="filter-list">
<!-- Filter list tags -->
</div>
<div class="pivot_field">
<span class="pivot_header2">Row Label Fields</span>
<div id="row-label-fields">
<!-- Row label tags -->
</div>
<!-- etc... -->

[alexhgreen07]

A change for this has been submitted as a pull request: #24. If this change is accepted we can close both of these.