When resetting added file, Jam data stays in "toSyncJam"

[tiesselune]

When adding a file to git index, then resetting it out of the index, the file sha-1 stays in the "toSyncJam" file, and thus is pushed on next git jam push, when it's not even commited.

Resseting files should remove sha-1s from that file.

[tiesselune]

There seems to be no way of knowing when a file is reset from the index. Which means that files WILL be copied on git addin the jam repository.

In order to avoid pushing unecessary jam files to the remote, we could use the pre-push hook to only push jam files that are being pushed in a commit.

By default (without the pre-push hook) everything will be pushed.

Which means there should be a way to GC the jam folder at any moment, by implementing a manual git jam gc command, to clean the local jam repository, and avoid pushing unnecessary files when the hook is not set up.