Implemented local default config file

With this change, if `eslint` is run without specifying a config file,
a search will be performed for an `eslint.json` config file.

The search will begin in the current working directory, and recurse
upwards until the filesystem root is reached.

If no `eslist.json` file is found, then the default `eslint.json` in the
eslint application directory will be used.
Fixing ESLint errors
Merge pull request #303 from ilyavolodin/eslint_errors

Fixing ESLint errors
Updating look up algorithm for local config files

* Local config files must now be named `.eslintrc`
* Options specified in local config files will be merged with base,
default eslint.json config
* Local config files will be looked up relative to each file being
linted
* Local config files are cached by directory for performance
Protecting private method

Moving `getLocalConfig()` off the `Config.prototype` since it is not
being unit tested and is not designed to be called publically.
Added further instructions for multiline test cases.
Merge pull request #313 from malandrew/patch-1

Added further instructions for multiline test cases.
Keep test filename inline with rule name

`dot-notation` is `dot-notation` in `eslint.json` and the rule is at `lib/rules/dot-notation.js`. This change just keeps the rule test named the same as the rule it represents.
Rename test for smartereqeqeq.js to smarter-eqeqeq.js

Keeping test file name inline with rule name and rule filename.
Merge pull request #315 from malandrew/patch-3

Keep test filename inline with rule name
Merge pull request #316 from malandrew/patch-4

Rename test for smartereqeqeq.js to smarter-eqeqeq.js
Fixed warning when unused var declared as param in FunctionExpression/Declaration can be ignored because later param is used
Added link to roadmap and JSHint feature parity list.
Removed console.log in tests.

Note: check why `npm test` didn't catch these.
Updated docs for no-unused vars rule.
Merge pull request #318 from malandrew/no-unused-var-ignores-unused-args-when-later-args-are-used

Allow unused FunctionExpression/Declaration param when following param is used (fixes #311)
Merge pull request #300 from sethmcl/local_config_file

Implemented local default config file
Merge pull request #319 from malandrew/patch-4

Added link to roadmap and JSHint feature parity list.
Fixed bug where JSHint was using the wrong file in lint task
Change default on to be errors instead of warnings (fixes #326)