Fix to help with the changelog for a PR build.

This adds a BuildData as an Action for a build that represents the last
build for this particular PR.  This ensures that GitSCM uses the
appropriate revision when determining the changelog.
Fixes issue where we are unable to get the author email on triggers

Sometimes the GitHub API throws a NPE when attempting to get the user for
a PR; this information is optional and shouldn't cause the trigger to
fail.
- when using a repo from an organisation the owner.login field is null. Try to fetch the owner name from html_url instead which doesn't rely on the owner object - fixes exception and issue #18365
- fix isUserMemberOfOrganization method by using the org.hasMember method instead of iterating over the members array (the latter didn't seem to return all members of an organisation in some circumstances)
- check if a pr is mergable on comment aswell - not only on pull request creation. Fixes building of the merged pull request when triggered by comment
- fix some logging spam and prevent unneeded exceptions
Fixed a typo
Issue #100: ability to include log details in commit comments
Merge pull request #88 from valdisrigdon/handle_owner_email_npe

Fixes issue where we are unable to get the author email on triggers
Merge pull request #99 from Mailaender/patch-1

Fixed a typo
use the StringBuilder for whole message
Do not change behaviour without notice. Set default to not use logExcerpt
Merge branch 'logExcerpt'
Merge pull request #15 from Memphiz/loggingspam

- fix some logging spam and prevent unneeded exceptions
fix forgotten variable change and logging
Merge branch 'fixorganisation'
Merge pull request #16 from Memphiz/mergedprtrigger

- check if a pr is mergable on comment aswell - not only on pull request...
Merge remote-tracking branch 'valdisrigdon/changelog'
remove unused imports

Conflicts:
	src/main/java/org/jenkinsci/plugins/ghprb/GhprbBuilds.java
	src/main/java/org/jenkinsci/plugins/ghprb/GhprbTrigger.java
remove unused import
don't use string concatenation in log messages