Css Changes for ".thumb-item" class in gallery section

--  removed ".thumb-item-head-wrapper" and "thumb-item-head" classes as
they seem pretty redundant, move margin information from
".thumb-item-head" to ".thumb-item"
-- removed p tag under ".thumb-item-head-wrapper" and move its id tag
value to child a tag's href attribute
-- this should follow exactly the same markup as ".thumb-item" except
without ".thumb-item-title"