* Allow messages applications to skip the compile sources phase
By default, simple iOS sticker packs created in Xcode do not include
a compile sources phase. This change will allow messages applications
with an empty list of sources to skip that phase entirely.
* Add support for launchAutomaticallySubstyle in run schemes
This is especially important for simple iOS sticker packs that require
this run scheme setting to be set to 2 in order to run the scheme
properly.
* Add commandlineArguments to XcodeGenKit Scheme specifications
* Update xcproj reference, format code, cleanup usage of
commandlineArguments in ProjectGenerator
* Update docs, CHANGELOG and equality checks in Scheme.swift
* Doc update
* Update fixture tests to have command line arguments. Fix remaining issue
with Scheme creation through "Test Scheme"