first implementation for the FileManager
added parent directory for event files
Added test project for the eclipse plugin
Added a way to generate and get the workspace ID

I also added a test to test that we I do generate a valid ID (non empty) and to make sure that it's always the same (for the same workspace)
renamed parent to rootDirectory
Added the workspace ID in front of the changed resource path

See title. It's descriptive enough
fixed bug when computing the event file names
added method to set the root directory
Merge branch 'master' into filemanager
moved initialization inside the setwriter method
Modified the persister so it uses the FileManager. It no longer accesses files itself
Merge pull request #11 from caiusb/workspace-id

Added the workspace-ID to every changed file
reordered methods
fix bug. Parent directory was not created
implemented the write method in FileManager
organize imports
removed the commitChanges method. Formatting
removed the need to create the file when retrieving its path.
code cleanup
Initial snapshot code

First try. Will work some more on it