#19 #18 changed the way the API routes work, post now supported

The old way produced too much code duplication and would be too massive
and hard to maintain.

Instead, added a way to validate the command and use an argument parser
to translate the URI args into Redis-rb args.  Plus we can use a
response builder to build us a json response.

However any command can be run right now by sending it to the
endpoint, probably not a good thing.
 #19 added a basic argument parser and response builder
 #3 made the config object be created and stored in rackdis singleton
 #3 set the options for redis the client in a better way
 #3 made merging the config options work better

Now the following priorities exist:

1. command line option
2. config file
3. defaults in config class
#20 added logging

Can log to a file by setting
* :log: in config.yml or
* -l|--log <location> at command line

Locations can be set as:
* nil/none          = /dev/null
* STDOUT, stdout, - = standard output
* STDERR, stderr    = standard error

Levels can be set as:
* shutup
* error
* debug
* info
* warn
made rake routes work
#20 logged some stuff in the redis facade

- info: the equivalent redis command
- debug: the args passed to the redis client
rescued from all errors and returned 500

TODO make this more intelligent, provide relevent HTTP error codes
added Rack::Cors to provide cross origin resource sharing
added some basic specs for the api and arg parser

basic list command endpoint tests
basic set command endpoint tests
made valid_command! check that the command is safe
 #3 added a method by which to enable unsafe commands

these are commands which could break the redis server or alter the
environment in ways that an API client should not be able to
removed redundant method, added TODO for unsupported methods
#3 added config option to force enable commands
added a post route to batch process commands

This is just '/v1/batch' with a parameter 'commands' which can be just a
newline separated collection or json array of commands to run all at
once.  This could allow execution of MULTI/EXEC commands but is as yet
untested.
enabled the ability to set the redis server
Merge branch 'master' of github.com:penguinpowernz/rackdis