add support for comma-delimited list of configuration directories
Specs no longer use "echo -n" as a test shell command

The -n option to echo is only supported by certain shells (e.g. bash) and as a result the tests can fail on certain platforms - OSX being one example. This removes the use of the -n option and adjusts expected output values accordingly.
Merge pull request #572 from tleach/mac-specs

Specs no longer use "echo -n" as a test shell command
Merge pull request #568 from grepory/multiconfigs

add support for comma-delimited list of configuration directories
[config_dirs] :config_dir -> :config_dirs, as it's now an array
Merge pull request #573 from portertech/config_dirs

:config_dir -> :config_dirs, as it's now an array
allow empty defaults for command tokens
¯\_(ツ)_/¯
Merge pull request #577 from piavlo/feature/empty-client-attributes2

allow empty defaults for command tokens
exited?() can let nil exit statuses through
extension post_init() hook, within event loop
Merge pull request #578 from portertech/extension_post_init

extension post_init() hook, within event loop
Merge pull request #579 from portertech/nil_exitstatus

exited?() can let nil exit statuses through
[docs] updated changelog
Merge pull request #580 from portertech/docs

[docs] updated changelog
minor version bump, 0.10.1
[redact] stop redact_passwords() from mutating settings etc
Merge pull request #584 from portertech/redact

[redact] stop redact_passwords() from mutating settings etc
[docs] updated changelog for 0.10.2
Merge pull request #585 from portertech/docs

[docs] updated changelog for 0.10.2