Add greater control over grid styles (more options and layout possibilities)

[postmastersteve]

Grid styles currently allow users to choose between a rollover style or a text below style based on our old grid paradigm. Now that grid styles are much more flexible and can be applied as styles, we can improve the feature with more options.

Ideas:

• ability to choose the layout of title, image, description, and read more (e.g. title above image above desc. above read more. Or image on left with title, desc. and read more on the right)
• animation control as you scroll down a layout and reveal grid items (e.g. flip-in or zoom-in or slide-up)
• ability to list categories applied to a post for each grid item (e.g. a grid item for a post might be in a "Couples" and "Engagement" category; they could be listed)
• bring back the AJAX-loading of content inline with the grid like P5 could do
• choice between consistent column width or consistent row height for masonry
• automatic image size options based on a stylistic choice, reducing the need for users to get a PhD in grid min-idea-max size controls (e.g. "maintain column count" or "max width of X" or "max height of Y" etc.)

[postmastersteve]

+1 Cory Ryan Photography ticket 192827

[postmastersteve]

+1 Sara Forrest ticket 193933 wants ajax loading of blog grids

[postmastersteve]

+1 Rachel Thatcher ticket 194299

[benjamintennant]

+1 Paul Meachen ticket 217704

[benjamintennant]

See https://github.com/downshiftorg/prophoto7-issues/issues/700 and https://github.com/downshiftorg/prophoto7-issues/issues/583 for related