Increment project version to 0.1.3

Changes since the last version:

- Added Clojars badge and Travis CI badge to README

- Small fix in log4j.properties

- Fixed a test helper that specifies a relative path to leiningen; it
  now assumes that an executable `lein2` can be found in PATH
add credits for contributors

[~/dev/weatherbill/projects/docbrown]$ find -iname '*.clj' -exec git blame {} \; | grep Davis | wc -l
1144
[~/dev/weatherbill/projects/docbrown]$ find -iname '*.clj' -exec git blame {} \; | grep Alice | wc -l
2944
[~/dev/weatherbill/projects/docbrown]$ find -iname '*.clj' -exec git blame {} \; | grep Galkin | wc -l
2649
[~/dev/weatherbill/projects/docbrown]$ find -iname '*.clj' -exec git blame {} \; | grep Steve | wc -l
4662
[~/dev/weatherbill/projects/docbrown]$ find -iname '*.clj' -exec git blame {} \; | grep Khalsa | wc -l
511
[~/dev/weatherbill/projects/docbrown]$ find -iname '*.clj' -exec git blame {} \; | grep Rama | wc -l
0
[~/dev/weatherbill/projects/docbrown]$ find -iname '*.clj' -exec git blame {} \; | grep Chagnon | wc -l
1258
[~/dev/weatherbill/projects/docbrown]$ find -iname '*.clj' -exec git blame {} \; | grep Richman | wc -l
1108
[~/dev/weatherbill/projects/docbrown]$ find -iname '*.clj' -exec git blame {} \; | grep Silva | wc -l
405
Add support for hybrid backend, plus minor changes.

Make Mandoline aware of hybrid mk-schema.
Update protocol documentation. Make a couple more
chunk store testing functions public so other backends
can use them.

Also a couple of minor formatting changes.
Increment project verison to 0.1.4

Changes since the last version:

- Contributors are credited in README

- Fixed inaccurate docstring on the versions method of the Connection
  protocol

- Added alias for the hybrid-s3-dynamodb backend