Adding a utility method for adding host entries

As much as this is a infrastructure-smell in the linux world, adding
hosts entries is still all to common in the windows world. This method
allows host entries to be configured to meet that need.

It can also be used when developing with vagrant to make sure that the
master and agent vms can see each other properly.
switching method to use powershell wrapper
removing unused powershell command
renaming method to add_system32_hosts_entry
(gh-472) refactoring method so that is only supports windows and will raise error on other platforms
(QENG-846) Centralized dated log path generation, and added options for specific log paths

Before, the latest link was hard to use since it jumped around, and you couldn't really get at
the timestamped log path itself because it was hidden in the log_path function.  This work
separates out the timestamped path generation into a static method so that it can be used
anywhere, and adds the current usages of it to the global options, so that they can be used
for other purposes, such as the use case for this issue: copying other files to this location
Allow overriding Docker image entrypoint

Using docker_image_entrypoint
(QENG-1340) Add GitHub PR refspec to install_from_git

 - When testing out Jenkins job configuration tweaks that must coincide with source
   changes, it can be useful to have Beaker be aware of the GitHub refspec.  This
   allows SHA references to GitHub commits / PRs that have not yet been merged,
   without having to jump through a number of additional job configurations to gain
   access to the appropriate commits.
 - Note that this does have performance implications, as performing a fetch will take
   longer on the first time.
(QENG-1340) updated spec tests to match fix for this issue
(QENG-688) made default log_level info rather than verbose
(QENG-526) A friendly way for Beaker to set environment...

... variables for SUTs

- add support for option :host_env, it can be set in the host
  configuration file
- requires updating each host so that sshd allows remotely setting
  environment variables
- add host.add_env_var(key,val) and host.delete_env_var(key,val) for
  using in test writing
(QENG-1476) drop blimpy hypervisor from beaker

- replaced with aws_sdk
fixing tests for add_system32_hosts_entry method
(CFACT-160) Add cfacter wrapper method

Used by the Native Facter (cfacter) project to run acceptance tests.
(QENG-1430) Added accept_all_exit_codes option to host exec calls

QA was having issues with errors occuring when they'd like to have failures, since the specific
error codes are forseen and specific failure cases.  In order to help them with this use case,
I've added the accept_all_exit_codes option, which will not error on unacceptable exit codes,
defering to the test above to deal with the command's exit code as a failure or otherwise.
(QENG-1430) added spec for accept_all_exit_codes being explicitly set to false
(QENG-1000) Ensure that add-el-extras works on all rhel platforms

The --add-el-extras options was only working for platform strings of the form
el-(5,6), which meant that you couldn't have beaker add the el repo on a
'centos' platform for instance.

Change makes more use of the Beaker::Platform attributes and checks
other rhel variants (centos, scientific, and the 'redhat' variant is
another platform label used for rhel I believe).
(QENG-1000) added oracle support to this fix
(MAINT) fix broken spec test

- fix broken spec test
- add check for deprecation warnings during spec testing
(MAINT) rpm returns 1 if package already installed