Buddypress connector implemented

[kidunot89]

trafficstars

Partially resolves #1093

Summary checklist

• [x] activity callbacks tested and passing.
• [x] group callbacks tested and passing.
• [x] option callbacks tested and passing.
• [x] xprofile callbacks tested and passing.
• [x] callback_xprofile_group_before_save and callback_xprofile_field_before_save callbacks added to the BuddyPress connector class to provide a more stable method of capturing the incoming field/field group action that doesn't rely on $wpdb->insert_id.