Add symbolic link storage
Add symbolic link storage

* Adds a symbolic link storage for developers. To enable it, put this
  to your config: COLLECT_STORAGE = u"flask.ext.collect.storage.link"
  then run your `collect` script to create all the links from the
  static folders to the intance folder.

* NOTE only files are symlinked, not folders!

Signed-off-by: Yoan Blanc <7e8c88beed64bd6a341c3085bc82ac100e832f6e@cern.ch>
Co-authored-by: Kamil Neczaj <f5effa4f8fb04510feb8c36db9502b05ce6bf54d@cern.ch>
Reviewed-by: Jiri Kuncar <2bdffcb416fed3002465740d19a053a39918cbe5@cern.ch>

minimind/Flask-Collect