Add missing $is-input argument

Fixes Sass compile errors if you've included $is-input in custom button classes with Foundation 5.2. Related to https://github.com/zurb/foundation/issues/4871
[FIX] @import "type" not necessary
!important statement missing for tables

Visibility classes for tables are not working as expected in all cases due this missing `!important`.
If it's missing they got `display: inherit !important` which results in rendering issues.
Fixed border styles for inputs. 

Now we can set unique border properties for all sides, with use variables.
Use a normal for loop

The alternative being combining `for…in` with `hasOwnProperty` I thought using the vanilla loop was preferable.
Fix: disabled dropdown buttons should not open

Fixes #5370
Fix joyride error

When the joyride is included on the page but hasn't been started yet,
the keystrokes events are still catched and we end up with a JS error
on `go_next` or `go_prev` functions.
This fix checks that the joyride is on screen before calling theses callbacks.
Skip unavailable previous element

The same way we skip missing next elements we should skip previous missing ones.
Fix: warning buttons style missing on topbar
grouped $topbar-dropdown vars together. Add $topbar-dropdown-link-color-hover for the option of having a separate color for hovering drop elements. Dropdown elements previously had an option for a text color, but not for a hover text color
Moved shade variables above colour variables
Added whitespace
Remove unused attribute in Tooltip Advanced doc

The Advanced section on the Tooltips page has the attribute `data-options="disable_for_touch:true"`, which is not used in the rendered HTML (it's actually the opposite) or is relevant to this section.
Button text adapted according to the HTML example
fix $topbar-menu-icon-color-toggled not working b/c of wrong div selection. Then fix top-bar @include hamburger from overrideing $topbar-menu-icon-color-toggled on hover
pass "" to hamburger($hover-color) instead of leaving it empty
there is $topbar-arrows boolean switch, but no $topbar-dropdown-arrows switch to turn off dropdown sub nav arrows. Added that with an if statement and var
set max width for textarea
typo
remove sass 3.4 functionality for now, causes issues with libsass and sass 3.2