this commit fixes #315

Changed border color for the arrow to make it more legible.
Fix for issue #315

Based on @thomaspark 's suggestions. Included the fix in variables.less,
and compiled with grunt swatch:paper to generate .css and .min.css
files.
Revert "Fix for issue #315"

This reverts commit 4ef3b17300523a79ebfa3a7221eb5803d42d4129.
Revert "Revert "Fix for issue #315""

This reverts commit e4c2332657a50335c20ce56771ef2ebcfc97a2d2.