Saving the known projects
Remembering which projects were touched in a session

And snapshotting only those. This should save us the hassle of having
to snapshot every time when eclipse starts. Also, we will always have
the minimal amount of snapshots needed to replay. This should be
kind on our storage.
This method returns the name of the zip file

Just the like the other overloaded one.
I am recording the snapshot event even if the project is not java

Since I am taking it, I have to record it.
Extracted a few methods

This should make the code easier to read and understand
Removing the zip files after I finish a test
Testing to make sure that I snapshot the required projects only
Merge pull request #43 from caiusb/snap-opt

Optimizing the snapshots