Fixes elastic#627

* Fixes non UTF-8 surrogateescapes 

Surrogate escapes in Unicode (non UTF-8 encoding) will be properly escaped with backslashes when encountered, versus breaking the transport layer.

* Removes erroneous bytes decode and reraises

Fixes to re-raise exceptions with different reasons
Removes erroneous bytes decode where bytes are desired

* Adds test for surrogate escapes in body

Tests that a surrogate escape sequence is properly escaped
with backslashes to produce valid UTF-8.

* Use proper byte sequence for surrogate

* Use if/else versus pass

* Proper Unicode surrogate escape

Use a Unicode Surrogate that properly escapes in both Python2 and Python3

* Passing test once surrogatepass is used

Updating test to pass once surrogatepass is used

* Use surrogatepass instead of backslashreplace

This replicates behavior between Python 2 and Python 3

* Fixes whitespace

* Simplifies with no exception block

Since `surrogatepass` will only ever explicitly occur when there are surrogate bytes encountered, there is no need to let the error throw and catch it, also uses single-quotes for consistency.

* Fixes Unicode Surrogate Escapes in request logging

This is the same fix as accepted for ElasticSearch requests, except applied to the request logging mechanisms.

Bring `tox.ini` up to date with `setup.py` and `.travis.yml`.

* Update cat.py

* Update tasks.py

Fixes elastic#660, thanks @juke1