added plugin lwrp
added sensu_plugin resource to test cookbook, added test plugin file
swapped "::" operator style for uri style, allowing future schemes (such as ftp)
cleanup unnecessary ternary op
default to current cookbook if no cookbook provided in uri
cookbook_directory attribute, supports plugins nested in cookbook files directory
additional tests for sensu_plugin attributes
Merge pull request #251 from sensu/plugin_lwrp

Plugin LWRP
[windows_extensions] use multiple <argument> elements in windows service template, specify extensions dir
                     - ensure certain common/default paths have the correct permissions
Merge pull request #252 from portertech/windows_extensions

use multiple <argument> elements in windows service config, specify extensions directory