factorize code about masonry temple
add text to masonry template
add ds-gallery-category support function
add gallery categories navigation template
add support to selecting root gallery using dsframework-root-gallery-category custom field
add support to selecting visible galleries using comma-separated list of slug in dsframework-visible-gallery-categories custom field
fix link issue
Merge pull request #33 from ciotto/gallery_category_navigation_template

Gallery category navigation template