0.14.1 flex cleanup

update release file paths to point to 0.14.1

apply a special bg-color class to the body element when the Dashboard component is on screen to work around some flexbox, chrome, css shenanigans.  sigh.

Backport fixes to 0.14.1

fixes #1855 - prevents broken links in the activity feed for entries regarding the addition/removal of cards on dashboards.

Resolves #1714

fixes #1855 - prevents broken links in the activity feed for entries regarding the addition/removal of cards on dashboards.

Remove flexbox on dashboard grid to workaround Chrome 48.0.2564.97 bug

Allow nil values when filtering against DateTimeFields

Serialize cards as hashes

100x faster query builder & cards  #1726

Visualizations refactor

switch serialized cards over to hashes instead of url path elements.  this addresses the issue with long SQL queries generating large referer headers that cause Jetty issues.

More robust metadata handling if we don't have field_values

More docstrings