Added support for Orchard 1.7

Hello, this is the pull request to add support for Orchard 1.7. Other changes include:
+ Exclude the _Backup folder, which was created by Orchard to store old
modules
+ Import from code: beside the 'Generate from source' that scans the
whole site, new options were added to generate from a specific module or
theme
+ maybe more, don't remember :P