removing unnecessary null check

because a String concatination is being performed on the line above,
even if the 2 values are null (which worst case, they would be an empty
String) we will always end up with a String.
security fix

no need to tell the word what URL and token is being used to trigger
the remote job ;-)
fixing type-o
updating POM file in preparation for release

- changing Jenkins version (1.541 —> 1.509)
- excplcitly including the version of the maven-hpi-plugin to solve a
build issue (as suggested here:
https://groups.google.com/forum/#!topic/jenkinsci-dev/AvLG9MmqEuU)
- fixing some indentations
new functionality: optionally failed build

Default behaviour is to fail the build if the remote build fails.
If this options is enabled, the build will NOT fail if the remote build
fails.