alpha-5

Changes since alpha-4:

• rebar3 now bootstraps itself
• app compile fixes on app info contents and config inheritance
• dropping ErlyDTL and going to Mustache for smaller executable sizes
  and faster load time on small CPUs
• dropping erlydtl compile command, ErlyDTL task moved to a plugin
• default dependencies are always fetched in the right place and don't
  need to be copied across profile runs
• escriptize fixes
• unlock command added
• resolving/avoiding clashes when a rebar3 dep and an application
  dependency conflict together
• profile deduplication (rebar3 as test,test,prod,test eunit returns
  the profile/directories for prod+test)
• upgrade command bugfixes to recognize promotion of transient deps to
  top-level deps
• support template when rebar3 is run as an embedded library
• some optimizations
• parse transform support is better in erl_opts
• fixes to package handling
• fixes to rebar3 deps