added configure and update funcs for hosts module
Updated host locators and update func for host modules
select/update template while creating OS
moved helper function from base class
Fixing CLI User tests.

* The User command in foreman does not allow for getting a record's
  information (using the ```info``` argument) using ```--login```, only
  ````---id````. So I have fixed user tests so that ```login``` is used
  for assertions and updates.
* I noticed that data from test modules were getting overriden by the
  default data sets included in
  ```robottelo/cli/metatest/template_methods.py```, so I fixed it as
  well.
* Updated CLI base ```exists``` method to return a
  ```SSHCommandResult``` object instead a single record from Foreman.
* Updated all CLI tests that use ```exists```.
Merge pull request #302 from omaciel/fix-cli-user-tests

Fixing CLI User tests.
fixed pep8 issues
instead of None using kwargs
Merge pull request #295 from kbidarkar/fix-hosts

 	added configure and update funcs for hosts module
merged import statements
Moved URL constant to constant.py and renamed them
moved URL to constant.py
blank line at end of file
Merge pull request #300 from sghai/os-test

select/update template while creating OS