[FIXED JENKINS-24676]: Give the user a readable error message when testing the connection instead of stack trace if their credentials are incorrect.
Various fields, especially lastFetchInstance, should be transient as they are fetched from EC2 anyway.
Fixed bug that caused infinite loop of NullPointerExceptions during provisioning of windows instances.

Signed-off-by: Stefan C. Mueller <scm@smurn.org>
Merge pull request #113 from smurn/master

Fixed bug that caused infinite loop of NullPointerExceptions
Merge pull request #112 from jglick/transient-lastFetchInstance

[JENKINS-24938] Various fields should be transient
Merge pull request #108 from recampbell/JENKINS-24676

[FIXED JENKINS-24676]: Give the user a readable error message
JENKINS-25209: Add "reboot slave after build" for a slave template

Adds slave template option to reboot a slave after a build
Once reboot commences the slave is monitored, reconnects are started and
the slave is reenabled once reconnect succeeds.
Fixes NPEs in tag handling
Make constructors more tolerant of null-strings.
Fix EC2ComputerLauncher switch state handling and breaks-to-label
Change minimal dependency to 1.541 to utilize jenkins.util.Timer
A reboot future must be transient
Merge branch 'JENKINS-25209' into develop