simplify manager actions in a "pythonic" way
never set a mutable as default argument
remove unused imports
manager: rename some classes (with backwards compatibility)

* `_Msg` to `_Message`
* `ManagerMsg` to `ManagerMessage`
manager: fix E203, E211, E221, E225, E231, E251

* E203 whitespace before ':'
* E211 whitespace before '['
* E221 multiple spaces before operator
* E225 missing whitespace around operator
* E231 missing whitespace after ','
* E251 unexpected spaces around keyword / parameter equals
manager: fix E713 ("test for membership should be 'not in'")
manager._Message: add constructor to define attrs
manager.Manager: rename `connected` (with backwards compatibility)
manager.Manager: simplify verification of "connected"
manager.Manager: add `is_running` (like `is_connected`)
manager.Manager: simplify verification of "running"
set version (there was none!)

(cherry picked from commit 1a88846d8d276f8903709a87a44b3e17528ddc28)
major cleanup of 'setup.py'

* set version as `asterisk.__version__` (it was using `None`)
* remove all the processing crap (of README, description, license,
  download URL)
* make PEP8 compliant

(cherry picked from commit 68553d55e78a5db06e5871db19e3b32a2aed830a)
rename old README

(cherry picked from commit 82701a5d6e3fb22fb9dd0896bbb1ce320cee2d7b)
remove old and obsolete doc, make and install files

(cherry picked from commit 61a750419b0d3bf8242c046f5637c104ec5d8e2b)
add basic README

(cherry picked from commit f700edf9d8a421b78303207f6bbbb1eb8afeb074)
backport of 01e333c from develop
backport of 6b4106d from develop
declared Python compatibility and development status

(cherry picked from commit f979b2681b00674f5a4964e49d7eb7005d082ba2)
setup: change fields of author and project URL

(cherry picked from commit e058e8d44086cb9331e80da18a837168ccb2445f)