projectGenerator ideas

In the last days I took some time to write a fork of xcodeProj.cpp to use a different method than pugi::xml

Reading carefully the actual code I've noticed some things that can be improved.

• Poco::UUID can be used to generate UUID
• OTHER_CPLUSPLUSFLAGS - there is something strange there. the template only has one parameter which is -D__MACOSX_CORE__ but if you use in your addon CPPFlags it adds to the template the following parameters: --D__MACOSX_CORE__, -mtune=native, -Wreturn-type, -Werror=return-type. we can remove them here or add to the template.
• local_addons folder can be removed when not used. OR better yet: created by demand.
• addons.make should not be rewritten as it is now. - https://github.com/openframeworks/projectGenerator/issues/258
• PG Doesn't overwrite info.plist if it already exist @2bbb

Done

• findArrayForUUID can be replaced. it tries to find UUID of the parent by looking for some children UUID. As everything is already set in emptyExample.pbxproj we can just have the parent UUIDs and not worring about traversing XML
• emptyExample.pbxproj I'm proposing all the general settings (appliable to Release, Debug and AppStore) can be moved to Project.xcconfig, so we have them in a more readable way, and the template gets smaller.
• SOURCE_ROOT is a variable used as a template placeholder to be replaced, but in some parts of the code it goes untouched to the final pbxproj
• void xcodeProject::saveWorkspaceXML is unused and can be removed
• https://github.com/openframeworks/openFrameworks/pull/6937
• https://github.com/openframeworks/projectGenerator/pull/289
• https://github.com/openframeworks/projectGenerator/pull/290

Review the unchecked items in the project generator, including addons.make, local_addons, info.plist, OTHER_CPLUSPLUSFLAGS, and Poco::UUID usage, along with xcodeProject::saveWorkspaceXML and emptyExample.pbxproj. Start by checking the related issue 258 and the existing project-generator templates; done means implementing and testing one clearly scoped improvement without regressing generated projects.