Refactor backuptool.

* Fix docstrings.
* Raise NotImplementedError if BackupTool.restore is invoked.
* Avoid os.sep; use os.path.join for buliding paths.
* Also delegate separator handling to os.path.join.
* Catch only OSError and tarfile.TarError.
* Use classmethod instead of staticmethod when the name of the class
  appears inside the method, to ease possible future refactoring.
* Simplify get_backups; reverse list in-place, filter None objects.
* Refactor get_backup.
  * Print warning on bad backup path.
  * Strip try..except to absolute minimum.
  * Ensure tarfile is always closed.
  * Print error on exception; return after callback.
* Do not mess with sensitive magic methods.
* Define __repr__ via to_dict; derive __str__ automatically.
* Move testing code to appropriate directory.
* Style fixes.
Merge pull request #834 from Renelvon/sane_backuptool

Refactor and initial tests for backuptool.
fix logger not rotating log files except on startup/shutdown

Signed-off-by: Thomas Stilwell <stilwellt@openlabs.co>
Merge pull request #835 from benemorius/fix-logfile-maxsize

fix logger not rotating log files except on startup/shutdown
Updates to documentation and .deb building

Updates to build .deb

Now builds a .deb and .rpm capable of using the new openbazaar launcher.

Had to modify the bash launcher so that it changes its current directory
over to openbazaar's installation folder in linux. May have to add
checks for OSX later, although I believe in OSX, this script will be
irrelevant as the application will be launched via .app launcher.
Migrate to bitcoin from pybitcointools. Fix #552.

* Replace privtopub with privkey_to_pubkey.
Merge pull request #842 from Renelvon/bitcoin

Migrate from pybitcointools to bitcoin.
Do not log image data in any circumstances
Silences unnecessary error log on shutdown.
Merge pull request #851 from gubatron/transport-shutdown-fix

Silences unnecessary error log on shutdown.
Merge pull request #848 from dionyziz/log_no_images

Do not log image data in any circumstances. (part 1)
fix/remove incorrect add_known_node() call

this should be (uri, pubkey, guid, nickname) but add_peer() will call
add_known_node() anyway, so just remove this call

Signed-off-by: Thomas Stilwell <stilwellt@openlabs.co>
make DHT::add_known_node() private

Signed-off-by: Thomas Stilwell <stilwellt@openlabs.co>
Merge pull request #865 from benemorius/fix-add-knownnodes-call

fix/remove incorrect add_known_node() call
Release checklists
Merge pull request #846 from dionyziz/contributing_release

Release checklists
Merge pull request #832 from gubatron/launcher-documentation-updates

Update launching documentation. Fix debian package (part 1).
Initial tests for setup_db
Refactor setup_db.

* Abstract schema at module level.
* Remove unused `remove_db`.
* Remove unused `main` suite.
* Use `with` aggressively.
* Import modules, not names; simplify imports.
fix default debug level in usage output

Signed-off-by: Thomas Stilwell <stilwellt@openlabs.co>