MDL-30740 repository: Add Microsoft Skydrive plugin

Thanks to Universidad Teconológica de Chile (INACAP) who funded this
work initially and LUNS who permitted this to be released open source so
I could continue to work on this.
MDL-30740 skydrive: show albums as essentially they are "folders"

If you create a folder in SkyDrive and add image to it, it will be calssified
as album and, this will not be listed without this patch.
MDL-30740 skydrive: Add filepicker navigation bar

In order not to get lost in the Sky.

We use a session cache to reduce repeated calls to the skydrive API,
storing the folder name each time we get a listing.

Original concept from Ruslan Kabalin, thanks!
MDL-30740 skydrive: bump version for core inclusion

Remove release name and maturity as these will now be inhereted from
core.
MDL-30740 Add repository_skydrive to standard plugins
MDL-30740 skydrive: convert muc to defined cache
MDL-30740 skydrive: improve repo metadata

* Add manage link
* Use realthumbnail for lazy loading images
* Add image height/width info
* Add author information to files