Move abstract service config to new key

- Moved abstract service factory config to "input_filter_specs" (from
  "input_filters").
- Now registering abstract service factory with InputFilterManager
  configuration, instead of top-level service manager.
Consume InputFilterManager instead of ServiceManager

- Updates the factory to inject the InputFilterManager instead of the
  ServiceManager.
- Updates the listener to rename "services" to "inputFilterManager".
- Tests continue to pass, as we're still composing a
  ServiceLocatorInterface implementation.
CS fixes

- trailing whitespace
Merge branch 'hotfix/input_filters_config_disambiguation'

Close #10
Do not use AbstractConfigService

- Resulting in false negative lookups for configuration.
Merge branch 'hotfix/config-retrieval'

Fixes an issue in configuration retrieval in the input filter abstract service
factory.
PSR-4 + QA toolchain

- Updates package structure to use PSR-4
- Adds Coveralls, php-cs-fixer, and Travis-CI support
Update getAutoloaderConfig()

- to point at correct directory
Add travis and coveralls badges
Merge branch 'hotfix/psr-4'

Close #11
README update with new structure