Ensure pushed vsn is reltool-compliant

Add helper scripts and git hooks to ensure vsn numbers are
reltool-compliant: only integers separated by dots.
Fix typo in ChangeLog
Add helper scripts for publishing to hex.pm
Prepare for 3.11.0
rename msg_defs to proto_defs

However, retain the msg_defs function and options, for backwards
compatibility.
add rpc record to generated flat tree
add service and roc metadata methods
add unit tests to provide coverage service and roc metadata methods
fix generated rpc methods as prop lists bug
multiple services support
add more unit tests
Merge branch 'lr/proto_service_metadata'
Prepare for 3.12.0