* added callout, cards, modified panels and added row-container

[audioscavenger]

• added row-container
• modified panel
• added styles auto loading for callout and cards
• I deliberatly added my name and version 3.4.0 in the comments but feel free to change that according to your own rules

@todo: maybe minify the styles?

• callout:

  • these are the callout from Bootstrap docs, plus a nice background, plus transparency and disabled options.
  • help updated
  • todo: none

• cards:

  • these are the cards from bootstrap 4, in a Pinterest column like fashion.
  • help updated
  • todo: add more options like set of cards, no radius etc

• row-container:

  • for rows inside a column, this fix a bug where the row would close too early. We just needed another shortcode for rows that's it.
  • usage: [row][column][row-container][/row-container]..[/column][/row]
  • todo: integrate an usage example in help.html

• panel:

  • now it's a real container with panel-heading, panel-body, panel-footer as per bootstrap definition.
  • help updated
  • todo: inform current users that the syntax has changed. They do not lose their data, but they need to rewrite the shortcodes though.

[MWDelaney]

Since these are not default Bootstrap 3 components, we won't be including them here.