Cleaner namespaced keyword -> string conversion

Utilize the `clojure.core/namespace` function to get ns of a keyword for
string conversion. Very minimal, but avoids a intermediate string & substring
operation. Also gives docstring to explain why `name` isn't being used and
renames to something less clunky.
Use as-str in base-element for consistency
Update CHANGELOG for upcoming 0.1.3
Move dependencies to dev profile
Merge branch 'as-str'
Merge pull request #81 from Prismatic/dev-deps

Move dependencies to dev profile
Add lein-release config
lein-release plugin: preparing 0.1.3 release
lein-release plugin: bumped version from 0.1.3 to 0.1.4-SNAPSHOT for next development cycle
Update .gitignore
Update README for 0.1.3