Add option to show which files were synced to debug sync process.

[Artem Zinnatullin]

Currently it's pretty hard to understand what bottlenecks the sync process.

An option to show what files get synched might help reveal files that are getting synced unintentionally and slowing down sync process.

@ming13 wdyt?

[Artem Zinnatullin]

rsync has two options that could potentially help in that:

• -n, --dry-run show what would have been transferred, we can run rsync twice if Mainframer was launched with this option to show what will be synced and then actually sync it.
• -v, --verbose increase verbosity

[Artur Dryomov]

Gradle projects sync a lot of files, but I can see where you are going. I think there is a room for the --verbose flag which will pass it to rsync and ssh.

[Artem Zinnatullin]

Main idea is to debug cases like:

mainframer make build

# And then run again

mainframer --debug-sync make build

So you could figure what files get regenerated and synced again even after "100%" incremental build.

Regarding ssh, I think that should be a separate flag