First step in implementing syntax for @import options, proposed in
https://github.com/cloudhead/less.js/issues/1185#issuecomment-13710620
(steps (1) and (2)).
I've implemented the 'multiple' and 'less' options. One could trivially
add 'once' and 'css' options as well, if there was need. Proposed
"silent" and "inline" options are deferred for future work.
I left the existing "@import-multiple" and "@import-once" syntax in place,
although the proposal is for this to be deprecated once the new option
syntax is in place.
It is up to the parser and compiler to rewrite them when those files are
imported by another LESS file.
- Modified and added test cases for import and import-once rules
- Fixed difference between client side and server side handling of relative urls
- Added a -rootpath option to lessc to specify another base path for the url
rewriting. By default, rootpath=''
