Screen Reader improvements for Accessibility, Contact form

Initial patch to change the Contact form to comply with Accessibility rules.

1. Changes made to the following files:
2. modified: css/civicrm.css
   Added class for use in other changes
3. modified: js/Common.js
4. modified: templates/CRM/Contact/Form/Edit/Address.tpl
5. modified: templates/CRM/Contact/Form/Edit/Address/city_postal_code.tpl
6. modified: templates/CRM/Contact/Form/Edit/CommunicationPreferences.tpl
7. modified: templates/CRM/Contact/Form/Edit/CustomData.tpl
8. modified: templates/CRM/Contact/Form/Edit/Demographics.tpl
9. modified: templates/CRM/Contact/Form/Edit/Email.tpl
10. modified: templates/CRM/Contact/Form/Edit/IM.tpl
11. modified: templates/CRM/Contact/Form/Edit/Individual.tpl
12. modified: templates/CRM/Contact/Form/Edit/Notes.tpl
13. modified: templates/CRM/Contact/Form/Edit/OpenID.tpl
14. modified: templates/CRM/Contact/Form/Edit/Phone.tpl
15. modified: templates/CRM/Contact/Form/Edit/TagsAndGroups.tpl
16. modified: templates/CRM/Contact/Form/Edit/Website.tpl
17. modified: templates/CRM/Custom/Form/CustomField.tpl
18. modified: templates/CRM/common/Navigation.tpl
19. modified: templates/CRM/common/additionalBlocks.tpl
20. modified: templates/CRM/common/jcalendar.tpl

All templates/CRM/Contact/Form/* changes are to give Screen Readers text and not just "Add" which is understood by sighted users because of position on screen.

Creates anchor for expandable links so that the "tab" key will stop on those items.

jcalendar.tpl changes "clear" to text with more specific meaning (e.g. Clear Deceased date, Clear Date of Birth)

This patch has been created to be used with v4.1.alpha2.

Let me know if anything additional is needed. Thanks.