Fixed style guide in asset unittest.
Asset asset_type and provider_id now updateable.

The rest call /asset/id [POST] now supports update of the fields
asset_type and provider_id (which is a type string now).
Fixed: Drush command metadata explode did not index its data to Solr.
Cleanup fase 1 codestyle.
Fixed problem when using symlink not adding new symlink to its stat cache.
Version 3.5.1-dev build 2098.
Change git:// to https:// for submodules to fix issues with http/https proxies
Merge pull request #111 from arjenk/feature/update_asset_type

Feature/update asset type