Fix for deeply nested output file

[JonathanTech]

Fix for issue #9

[mariocasciaro]

Hi, I'm actually aware of this problem and it should already be fixed in the nested-url branch, unfortunately I wasn't able to publish a new package, because I'm waiting for a PR to be merged on one dependency (rework-importer). I'll try to get it merged ASAP. In the meanwhile you can try to use the branch in your package.json:

"gulp-concat-css": "git://github.com/mariocasciaro/gulp-concat-css.git#nested-urls"

[JonathanTech]

I just moved over to this branch and it's still producing incorrect urls where my change wasn't.

../../../../../fonts/glyphicons-halflings-regular.eot

And here's the npm ls

├─┬ gulp-concat-css@0.1.4 (git://github.com/mariocasciaro/gulp-concat-css.git#0b8c9bf1233be5c0366b18521dc86132eaa57f7e)
│ ├─┬ gulp-util@2.2.20
│ │ ├─┬ chalk@0.5.1
│ │ │ ├── ansi-styles@1.1.0
│ │ │ ├── escape-string-regexp@1.0.2
│ │ │ ├─┬ has-ansi@0.1.0
│ │ │ │ └── ansi-regex@0.2.1
│ │ │ ├─┬ strip-ansi@0.3.0
│ │ │ │ └── ansi-regex@0.2.1
│ │ │ └── supports-color@0.2.0
│ │ ├── dateformat@1.0.8
│ │ ├── minimist@0.2.0
│ │ ├─┬ through2@0.5.1
│ │ │ └── xtend@3.0.0
│ │ └── vinyl@0.2.3
│ ├─┬ rework@0.20.3
│ │ ├── color-parser@0.1.0
│ │ ├── convert-source-map@0.3.5
│ │ ├─┬ css@1.6.0
│ │ │ ├── css-parse@1.7.0
│ │ │ └── css-stringify@1.4.1
│ │ ├─┬ debug@2.0.0
│ │ │ └── ms@0.6.2
│ │ ├── hsb2rgb@1.0.2
│ │ ├── mime@1.2.11
│ │ ├── rework-inherit@0.2.3
│ │ └── rework-visit@1.0.0
│ ├─┬ rework-importer@0.3.1 (git://github.com/mariocasciaro/rework-importer.git#daa585d3218e7d166be4a75afe965059e179e176)
│ │ └─┬ css-whitespace@1.1.0
│ │   └── debug@0.7.4
│ └─┬ through2@0.4.2
│   └─┬ xtend@2.1.2
│     └── object-keys@0.4.0