Added and exported method `test`

This commit renames the primary function to `parse`, adds a method named `test`
and assigns `module.exports` to `parse.

The `test` method lets one test a string for the existence of front-matter. It
takes a string, and returns true if front-matter is found and false if front-
matter is not found.

The primary front-matter function is renamed to parse, but does not change the
way the module is used.

The `test` method will differentiate between strings with empty front-matter and
strings that don't have any front-matter which differentiates it from the
primary `parse` function which returns an attributes object no matter the
presence of a front-matter header.
Adds clean, test, node_modules tasks to Makefile
renames test file
Drops support for Node.js 0.6, adds 0.11
DRY up the code a bit, expose regex.test() as fm.test()
Cleans up example files
Refactors tests, drops chai dep
Adds @bcomnes to contrib list
Fixes bug with running exports.test outside of the module
Adds fm.test(string) to the readme.