Price set display improvements on the event info page

As per comments from Dave - the display of multiple price sets on the event info page is not ideal; they are shown next to each other tend to blend together.

Instead of

Conference Fee - Member $ 340.00
Conference Fee - Non-member $ 500.00
Conference Fee - Alumnus $ 425.00
Dinner Choice - Steak $ 25.00
Dinner Choice - Chicken $ 20.00
Dinner Choice - None $ 0.00

(see attached for the current display 'problems')

We can pass CSS classes along with the event fee elements to allow styling which differentiates:

• event fee labels: class=fee_level-label
• price set field labels: class=price_set_field-label
• price set field option groups (i.e. label for radio, select or chckbox price set field): class=price_set_option_group-label
• price set field options: class=price_set_option-label

civicrm.css sets explicit style for option labels to indent them:
td.price_set_option-label

{padding-left: 3em;}

Here's an example of the new markup for a prices set with options:

<table class="form-layout-compressed fee_block-table"> <tr>
<td class="price_set_option_group-label">Conference Fee</td>
<td></td>
</tr>
<tr>
<td class="price_set_option-label">Member</td>
<td class="fee_amount-value right">$ 120.00</td>
</tr>
<tr>
<td class="price_set_option-label">Non-member</td>
<td class="fee_amount-value right">$ 150.00</td>
</tr>
<tr>
<td class="price_set_option-label">Student</td>
<td class="fee_amount-value right">$ 75.00</td>
</tr>
<tr>
<td class="price_set_option_group-label">Lunch Choice</td>
<td></td>
</tr>
<tr>
<td class="price_set_option-label">Chicken</td>
<td class="fee_amount-value right">$ 8.50</td>
</tr>
<tr>
<td class="price_set_option-label">Fish</td>
<td class="fee_amount-value right">$ 9.75</td>
</tr>
<tr>
<td class="price_set_option-label">Tofu</td>
<td class="fee_amount-value right">$ 7.25</td>
</tr>
<tr>
<td class="price_set_field-label">Dinner Guests</td>
<td class="fee_amount-value right">$ 55.00</td>
</tr>
</table>