Register plugin only one time when it's present in global and project mode
Add installer events
Fix tests on windows, fixes #3141
Merge pull request #3142 from francoispluchino/plugin-load-only-one-time

Register plugin only one time when it's present in global and project mode
Merge remote-tracking branch 'francoispluchino/installer-events'
Rename *-solve-dependencies to *-dependencies-solving
Merge remote-tracking branch 'origin/master'