Revamping class Directory: unnecessary methods removed; implementing directory tree printing recursion.

Testing pending.
Directory Tree Printing tests in progress...

Print directories is ok. Needs to implement FileFactory in order to continue tests; with files instead of only folders.
Added IDepurador and Depurador
Tree Printing tests complete.

Apparently, it works. Also, removed 'parent' attribute from FileSystem class. We won't be using it anymore.
Merge pull request #1 from ghalox/felix-edits

Felix edits
Final stage. Just have to finish Depurador and test.
Merge pull request #1 from paulomarcos/master

Debugger