.rtl.css (or --ext value) files must be excluded

[smmoosavi]

$ mkdir styles
$ touch styles/a.css
$ touch styles/b.css
$ ls styles/
a.css  b.css

$ 
$ rtlcss -d styles/
$ ls styles
a.css  a.rtl.css  b.css  b.rtl.css

$ rtlcss -d styles/
$ ls styles/
a.css  a.rtl.css  a.rtl.rtl.css  b.css  b.rtl.css  b.rtl.rtl.css

[MohammadYounes]

This is a duplicate of #64, for the time being you can set the destination to a different folder as mentioned here