Support for Convention-based scriptable pre/post executions

[dougrathbone]

As a developer it would be great to be able to define a script (MSBUILD or Powershell) that could be run pre and post the deployment of the web deploy package.

This would enable:

• a package with convention based filenames for pre/post ("predeploy_staging.ps1", "postdeploy_staging.ps1")
• A package with environment specific actions (copy "config-file_staging.dat" over "config-file.dat")
• the ability to handle which environment is being applied at run time "production" or "uat" or "staging"