Modify psake to support optionally retrying tasks a configurable number of times on failure so transient errors can be handled gracefully.

Usage:

task MyTask -maxRetries 3 { ... }
Modify psake to support optionally specifying a regular expression that can be used in combination with the maxRetries parameter to enable retry logic for only specific cases.

Usage:

task MyTask -maxRetries 3 -retryTriggerErrorPattern "Can't connect to database at this time"

This configuration will cause psake to retry MyTask only if an exception occurs where the exception message contains the phrase "Can't connect to database at this time".
Merge branch 'master' of https://github.com/rakutensf-malex/psake into rakutensf-malex-master

Conflicts:
	psake.psm1