rebar_config:is_verbose/0: fix variable name
rebar_log: use defines for log level numbers
Change default log level to 'warn' and introduce -q/--quiet
Write ERROR messages to standard_error device
Fix is_verbose/1 helper function
Merge pull request #184 from tuncer/logging

Fix log levels
inttest/rgen_1: double the timeout a second time

60s still seems to be too low, as it timed out for at least the R15B01
job of the timeout patch merge:
https://travis-ci.org/rebar/rebar/builds/15051701
https://travis-ci.org/rebar/rebar/jobs/15051703
Clean up rebar.config.script
rebar_dia_compiler: fix Dialyzer warnings
bootstrap: avoid trying to run 'debug' command

If you invoke 'make debug', then bootstrap executes rebar:main/1 with
the extra argument "debug" and rebar treats that as a command. There is
no such command.

Without this patch you will see the following on bootstrap:
Command 'debug' not understood or not applicable
Merge pull request #199 from tuncer/dia-dialyzer-warnings

rebar_dia_compiler: fix Dialyzer warnings
Merge pull request #200 from tuncer/fix-debug-bootstrap

bootstrap: avoid trying to run 'debug' command
Add a library template
Add command to rebar:command_names/0
Merge pull request #201 from fenollp/create-lib

Added a library template.
Merge pull request #198 from tuncer/clean-up-rebar-config-script

Clean up rebar.config.script
Merge pull request #190 from tuncer/quadruple-timeout

inttest/rgen_1: double the timeout a second time