Remove lfe_opts (suggested by Tim Dysinger)
Support settable plt dir for dialyzer

Allow rebar to use dialyzer plt files from an alternate directory
through the use of the REBAR_PLT_DIR environment variable.
Add Evax Software to THANKS file
Add file local variables where appropriate
Fix formatting (thanks Piotr Usewicz)
Add Piotr Usewicz to THANKS file
Add list-deps command
Add support for command-specific env for hooks
Adjust deprecation message
Fix eunit regression (reported-by Alexander Dorofeev)
Update mustache.erl
Add missing newline in port_compiler debug msg
Expand variables in replace overlay
Document so_specs
Fix code readability in port_compiler
Change logic to support more port env use cases

The logic changes from strict overrides to a hybrid for merging os_env
and defaults, whereby defaults are chosen if they are not set in the
os_env or if the defaults contains substitutions (at which point os
environment is substituted).

This still means that rebar.config works as it did before, where it
overrides or substitutes based on the use of $VAR, but that default
and os environment merging works such that the common cases of
providing CC or LDFLAGS in the users environment or command line work
as you might expect.  In that CC is overriden by the os environment
unless rebar.config overrides it, and LDFLAGS from the user environment
is appended or prepended based on defaults and rebar.config.

Addresses problems with https://github.com/basho/rebar/pull/71
Also keeps the fix for bug 255.
Merge pull request #75 from djnym/port_env_handling

Different fix for the OS environment vs Default environment
Merge pull request #69 from maxlapshin/master

I've added variable expansion in replace overlay
Document pull requests, branching and code style
Update known discrepancies: erl_scan corrected