Switched to using GridFieldExtensions module instead of Sortable Grid Field
Revert "Switched to using GridFieldExtensions module instead of Sortable Grid Field"

Gridfield extensions is 3.1 only...

This reverts commit 88f0cb30959c8e0df95df24ab1220a5d24441519.
Patched templates + code for 3.1 support
Switched to using GridFieldExtensions module instead of Sortable Grid Field
Revert "Switched to using GridFieldExtensions module instead of Sortable Grid Field"

Gridfield extensions is 3.1 only...

This reverts commit 88f0cb30959c8e0df95df24ab1220a5d24441519.
Patched templates + code for 3.1 support
Merge branch 'master' of github.com:nyeholt/silverstripe-metadata
Merge pull request #7 from nyeholt/master

3.1 updates to templates and DropdownField usage, as well as directly defining a Sort param to not rely on external extension