remove underscore dependency

resolves #14 by replacing underscore with lodash.defaults (and also extend-object)

code modernization

[ no functional change ]

recommit min file

resolves #13

bug in extender fn

resolves #12

convert to UMD pattern

resolves #8: UMD CommonJS wrapper

minify main js file

resolves #11: 51% reduction 👍

also retry normal $.ajax requests

update per #10: retry both Backbone.$.ajax and $.ajax requests (the latter can be disabled via setting)

send ajax request params with jqXHR object

exhaust return jqXHR return argument extended with ajax options, thus allowing jqXHR.type, jqXHR.url, etcetera - useful for determining the request path, type and other parameters

undo #7 change

this 'fix' was misplaced - belongs in your Backbone.js clientside app.js

Only retry 500-class request responses

update/fix for #6 - changed >= >>> <