Add HanoiDB backend support
Reverted changes to Makefile and edis_config.erl.  Added delete
case into call in write.
Basic HanoiDB config
Move test configurations into test directory. Add hanoidb config and
test config as well as Makefile target which runs tests using it.
getrange returns an empty binary object when the range requested
is impossible to produce or has no content not 'nil'.
Impossible ranges return <<>> empty binaries, not 'nil', fix the test case not the code.
No need to invoke rebar twice.
This was implemented, so let's use the hanoidb destroy/1 call.
Fix the test configuration files.
Library update
Fixes #17 by removing erldocs from the deps
changing rebar.config to fork eleveldb on production servers
fixed a type in eleveldb git path
Merge pull request #18 from vireshas/master

Using public git url for eleveldb on rebar.config
Back to our own eleveldb fork
implemented new loggin framework, lager
Merge pull request #20 from inaka/joachim_lager

implemented new loggin framework, lager
70/70 tests passed with the new lager logging framework
Merge pull request #22 from inaka/joachim_test

70/70 tests passed with the new lager logging framework
Two successful tests for keys