* Add return code for invalid args block

Return non-zero rc instead of None

* Added headers argument to get requests so that additional headers can be passed in similar to post reqeusts

* Added the option of always adding a particular header to a request. Also fixed unicode xml decoding error

* Adding additional comments to denote that a headers object is possible to pass in as a kwarg

* auto-doc all class constructor parameters

* Searchcommands: add full support for unicode

Python's cstringio doesn't support unicode characters,
when encountering them Exceptions are raised. We've
decided to use stringio instead, trading potential
performance improvements for full unicode support.

In Python 2, this may lead to a slight performance hit
since we're no longer explicitly using the native version.

However, in Python 3 stringio will automatically use the
native version if available and there should be no noticeable
performance changes.

* update assertion

* Make the explorer example compatible w/ Python 3

... by using the six library

* Update binding.py

*  Run CI against Splunk 7.2

* tests: relax restart timeout

* Fix ssl verify to require certs when true (#233)

- Correct logic to always look for cert files when verify=True
- Pass key_file and cert_file to handler from HttpLib
- Changed default value of verify to False for backward compat

* Preparing Release 1.6.6

* Cleaned up CHANGELOG.md

* Update version to 1.6.6 in User-Agent header

* Rev version of examples/searchcommands_app/setup.py to 1.6.6