Add rebar_lock_deps_plugin support to generate lock file
Add rebar.config.lock file for deps at 2.0.0pre1

This lockfile was generated Sept. 7th, for 2.0.0pre1.  To
rebuild from this file, call `make locked-all`.
Fix rebar.config typo
Update rebar.config.lock file to include YZ
Merge branch 'release/2.0.0pre1' into develop
Roll rel version to 2.0.0pre1