disallow legacy urls by default
no need for symbolize_keys option to json_decode and json_b64_decode
App#env
Content#env
configurable no longer calls methods on the plugin itself
use env variables instead of "command line" object
sanity check tests for changing convert/identify commands
renamed "use" -> "plugin"
setup_config -> set_up_config
removed unneeded app for testing
configure doesn't need yielded object
"add_processor" in configure block -> "processor"
"add_generator" -> "generator" in config block
"add_analyser" -> "analyser" in config block