Add 'is' keys for a few attributes
Override remote_server_addr with a default in Appium.pm
Add test for aliased tap method in Appium::Element
Update generated README and cpanfile

The updates are due to e41b5fc and b9edbec.
Use alias to allow desired_capabilities or caps as init arg

This is pending a fix for aliases an overridden attribute in a subclass
in MooX::Aliases - see haarg/MooX-Aliases#1.
Actually use aforementioned alias from 92e572d