Use a remporary file to run groovy scripts

Here documents (using <<-GROOVYSCRIPT) do not work properly on windows,
specifically Powershell. This commit switches to using Ruby's tempfile.
Allow attribute overrides to work properly
Use travis namespace for 'ci' rake task.  Fixes #202.
Merge pull request #203 from opscode-cookbooks/yzl/issue-202

Use travis namespace for 'ci' rake task.  Fixes #202.
Use executor['timeout'] for timeout in ShellOut in executor.execute!
Give timeout a default value (60) in the executor
Ignore Errno::ENETUNREACH until timeout
Fix a bug in default windows domain name

Domain name default value is set to nil: when the cookbook generates
winsw xml file template domainname is set to "".

Unfortunately winsw ignore the whole  <serviceaccount> part of the
config when domain name is not specified or empty.

In the end, when domain is not specified in jenkins slave, user is
ignored and jenkins service will run as administrator..
Update winsw version to 1.16

Version 1.13 do not support windows logon feature (starting a service
with a defined user).

See https://github.com/kohsuke/winsw/commit/7aa4018451e6d2ff252dd12d98d5f20552329d32
for more details.
Upgrade to ChefSpec 4 and fix CI
Use the run_state to store sensitive information

- Fixes #158
Switch to LWHRPS for everything

- Fixes #164
- Fixes #187
Handle nil values in credentials comparison

- Fixes #219
Add ChefSpec matchers for all LWRPs
Don't automatically restart after plugin installation
Add the ability to pass in a list of additional options in jenkins_plugin
Fix a typo in the Test Kitchen config
Specify actions and default_action in inherited resources

See https://github.com/opscode/chef/pull/1553 for more information
Set the private_key after authentication is enabled
Release v2.1.0