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.
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.