Using svn gem.
implemented available? method for svn_downloader

sign-off-by: Alessandro Palmeira <alessandro.palmeira@gmail.com>
Started to write the retrieve! (get) tests for svn_downloader.

Signed-off-by: Renan Fichberg <rfichberg@gmail.com>
Signed-off-by: Rafael Manzo <rr.manzo@gmail.com>
class SVN Downloader fully implemented
Revert "Using svn gem."

This reverts commit dba28381309ffab841d5632ca859610855d7866c.
Refactored svn_downloader.
Added svn_downloader acceptance tests and refactored git_downloader tests.
Added Repository support to SVN type.