added checking for unused vars to .jshintrc

build/build/app.js: line 37, col 33, 'baton' is defined but never used.
build/build/app.js: line 37, col 26, 'prev' is defined but never used.
build/build/compress.js: line 29, col 93, 'stdin' is defined but never used.
build/build/compress.js: line 29, col 86, 'stdout' is defined but never used.
build/build.js: line 49, col 55, 'complete' is defined but never used.
build/test/jasmine-node.js: line 31, col 53, 'runner' is defined but never used.
build/test.js: line 20, col 17, 'childProcess' is defined but never used.
lib/ripple/db.js: line 64, col 51, 'key' is defined but never used.
lib/ripple/dbfs.js: line 73, col 38, 'baton' is defined but never used.
lib/ripple/dbfs.js: line 73, col 31, 'prev' is defined but never used.
lib/ripple/dbfs.js: line 105, col 48, 'options' is defined but never used.
lib/ripple/dbfs.js: line 105, col 39, 'error' is defined but never used.
lib/ripple/dbfs.js: line 111, col 51, 'options' is defined but never used.
lib/ripple/dbfs.js: line 111, col 42, 'error' is defined but never used.
lib/ripple/dbfs.js: line 158, col 42, 'error' is defined but never used.
lib/ripple/dbfs.js: line 182, col 41, 'error' is defined but never used.
lib/ripple/dbfs.js: line 187, col 61, 'options' is defined but never used.
lib/ripple/dbfs.js: line 187, col 52, 'error' is defined but never used.
lib/ripple/exception.js: line 24, col 18, Avoid arguments.callee.
lib/ripple/omgwtf.js: line 63, col 42, 'baton' is defined but never used.
lib/ripple/omgwtf.js: line 63, col 35, 'previous' is defined but never used.
lib/ripple/platform/cordova/1.0.0/accelerometer.js: line 24, col 57, 'onError' is defined but never used.
lib/ripple/platform/cordova/1.0.0/camera.js: line 17, col 68, 'cameraOptions' is defined but never used.
lib/ripple/platform/cordova/2.0.0/bridge/contacts.js: line 91, col 54, 'index' is defined but never used.
lib/ripple/platform/cordova/2.0.0/bridge/device.js: line 19, col 49, 'args' is defined but never used.
lib/ripple/platform/cordova/2.0.0/bridge/device.js: line 19, col 43, 'fail' is defined but never used.
lib/ripple/platform/cordova/2.0.0/bridge/file.js: line 275, col 23, 'FileReader' is defined but never used.
lib/ripple/platform/cordova/2.0.0/bridge/file.js: line 300, col 23, 'FileReader' is defined but never used.
lib/ripple/platform/cordova/2.0.0/bridge/geolocation.js: line 30, col 11, '_error' is defined but never used.
lib/ripple/platform/cordova/2.0.0/bridge/geolocation.js: line 66, col 48, 'args' is defined but never used.
lib/ripple/platform/cordova/2.0.0/bridge/media.js: line 178, col 56, 'args' is defined but never used.
lib/ripple/platform/cordova/2.0.0/bridge/media.js: line 182, col 55, 'args' is defined but never used.
lib/ripple/platform/cordova/2.0.0/bridge/network.js: line 26, col 53, 'args' is defined but never used.
lib/ripple/platform/cordova/2.0.0/bridge/network.js: line 26, col 47, 'fail' is defined but never used.
lib/ripple/platform/cordova/2.0.0/bridge/notification.js: line 26, col 44, 'args' is defined but never used.
lib/ripple/platform/cordova/2.0.0/bridge/notification.js: line 26, col 38, 'error' is defined but never used.
lib/ripple/platform/cordova/2.0.0/bridge/notification.js: line 26, col 31, 'success' is defined but never used.
lib/ripple/platform/cordova/2.0.0/bridge/notification.js: line 30, col 50, 'args' is defined but never used.
lib/ripple/platform/cordova/2.0.0/bridge/notification.js: line 30, col 44, 'error' is defined but never used.
lib/ripple/platform/cordova/2.0.0/bridge/notification.js: line 30, col 37, 'success' is defined but never used.
lib/ripple/platform/cordova/2.0.0/bridge/notification.js: line 33, col 49, 'args' is defined but never used.
lib/ripple/platform/cordova/2.0.0/bridge/notification.js: line 33, col 43, 'error' is defined but never used.
lib/ripple/platform/cordova/2.0.0/bridge/notification.js: line 33, col 36, 'success' is defined but never used.
lib/ripple/platform/cordova/2.0.0/bridge/notification.js: line 36, col 50, 'args' is defined but never used.
lib/ripple/platform/cordova/2.0.0/bridge/notification.js: line 36, col 44, 'error' is defined but never used.
lib/ripple/platform/cordova/2.0.0/bridge/notification.js: line 36, col 37, 'success' is defined but never used.
lib/ripple/platform/cordova/2.0.0/spec/device.js: line 16, col 10, 'event' is defined but never used.