more robust @import regexp.

Author: darktable

build/build.xml

@@ -653,7 +653,7 @@
 
         <!-- replace imports with h5bp-import tags (part 1) this one wraps @media types -->
         <replaceregexp file="${dir.intermediate}/${dir.css}/${file.root.stylesheet}" 
-                       match="^@import *url *\( *'?([^'^ ]*)'? *\) *([a-z]*).*$" 
+                       match="^@import *url *\( *'?([^'^ ]*)'? *\) *([a-zA-Z, ]*);.*$" 
                        replace="@media \2{ /* h5bp-import: \1 */ }" byline="true" />
 
         <!-- replace imports with h5bp-import tags (part 2) -->