Add basic RTL support

[alaa13212]

Add basic RTL support

[cvrebert]

Having 2 copies of every LESS file doesn't seem workable/maintainable.

[cvrebert]

Attempts to fix #175.

[alaa13212]

What about writing rtl.less file.

@dir: right;
@import "bootstrap.less";

And mirror-mixins.less

.float(@pos) when (@dir = left){
  float: @pos;
}
.float(left) when (@dir = right){
  float: right;
}
.float(right) when (@dir = right){
  float: left;
}

.clear(both) {
  clear: both;
}
.clear(@pos) when (@dir = left){
  clear: @pos;
}
.clear(left) when (@dir = right){
  clear: right;
}
.clear(right) when (@dir = right){
  clear: left;
}

.text-align(center) {
  text-align: center;
}
.text-align(@pos) when (@dir = left){
  text-align: @pos;
}
.text-align(left) when (@dir = right){
  text-align: right;
}
.text-align(right) when (@dir = right){
  text-align: left;
}

// etc..

Then use

p {
 .float(left);
 .clear(left);
 .text-align(right);
}

[cvrebert]

Yes, that kind of approach is better.
You should read @mdo's comment in #6423 (comment) though. Seems he wants to start with just 1 widget/component and then proceed from there.

[mdo]

Yup, this has come up numerous times. It's way more difficult to try to review and manage a pull request that adds all this without first figuring out and documenting our approach with one component. There are other issues in addition to that, but we need to start small and go from there.

[alaa13212]

I will start in navs.less file. :)