Properties merging should work also inside directives #2035

The `_mergeRules` function is now called also for directives with rules.

I had to turn off jasmine tests for `merge.less`, because it was replacing
all urls by their assumed full paths. For example, the
`url(something.eot)` was changed into
`url(http://localhost:8081/test/less/something.eot)`. The result did not
matched with expected css and failed.

Note: I'm not sure why values order in source map changed. It does not
seem to be caused by my change, it was failing before I made them.