Fixes #7 -- read from settings file the json location

Add the ability to read a setting from .settings/com.palantir.tslint.prefs.
Also, update the RuleFailure class to have the ruleName property so it
doesn't crash.
Make the node reference TSLintPlugin.ID
Merge pull request #8 from gscshoyru/tslint-location-config

Fixes #7 -- read from settings file the json location