rearrange the example
fix for the fact that yaml parsing doesn't preserve ordering
added a particle class, aiming for a Z boson example
more specific installation instructions
added an environment setup script
documentation and questions: EventStore, Collection, Registry
documentation and questions: EventStore, Collection, Registry, Writer
Merge branch 'documentation' of github.com:cbernet/albers into documentation

Conflicts:
	include/albers/EventStore.h
commented the code: Reader, Handle
able to build on macos, need to test lxplus6
conditional for mac os x
Merge branch 'master' of github.com:HEP-FCC/albers
Merge branch 'macos_build' into macos_build_merge

Conflicts:
	README.md
Merge pull request #7 from cbernet/macos_build_merge

Macos build merge