Add support for dropdown border variables

[vicocamacho]

Add the Bootstrap variables for the arrow of the datepicker:

[korun]

Why we need these lines? O_o

[vicocamacho]

You are right, these are not necessary i removed them and now i am using the correct variable for the arrow border (@dropdown-border) 388f192

[vsn4ik]

👍 for merge.

[acrobat]

@vicocamacho can you add the variable also to the tbws2 less file? and add the parameter to the build.less & build3.less file with the color code currently in the datepicker(3).less file

[vicocamacho]

Sure, will do it in the next few days

[vicocamacho]

I don't know if you guys saw this, is this what was needed? thank you!

[acrobat]

Just add the variables to the build.less and build_standalone.less. Then this PR should be ready (will review it fully then!)

[vicocamacho]

is this correct? vicocamacho@6faf3b4

[hebbet]

will look into it in the next few weeks

[hebbet]

LGTM, thanks, merged.

[acrobat]

Maybe we should add a styling section to the docs, where we can describe this feature