[FIXED JENKINS-23294] Interpret X-Forwarded-Port

Fix documentation.

Reverts 66528e43 so as to make test cases more faithful to real behavior.

[FIXED JENKINS-21716] Set Content-Type header for env-vars.html

Signed-off-by: NOleg Nenashev <o.v.nenashev@gmail.com>

[FIXED JENKINS-20086] Allow disabling use of default exclude patterns (.git, .svn, etc.)

Reference: https://trello.com/c/doFFMdUm/46-filepath-getcomputer

Signed-off-by: NOleg Nenashev <o.v.nenashev@gmail.com>

[JENKINS-23595] - Fix makeFlash script bug with ImageMagick v6.7.9+

Fix a NPE when the 'properties' element is missing from the form's JSON

switched off alpha before colorizing temporary gifs when making animated balls. prevents colorize from applying fill to alpha channel. alpha is turned back on after colorize operation

[FIXED JENKINS-23481][FIXED JENKINS-23551] Send onOffline notification to master computer prior Jenkins restart

[FIXED JENKINS-23481][FIXED JENKINS-23551] Send onOffline notification to master computer prior Jenkins restart.

Introduces new overload `ComputerListener.onOffline(Computer, OfflineCause)`.

[FIXED SECURITY-134] Restrict access to admin monitor info page

[FIXED JENKINS-23526] Tolerate 'null' result when used creatively