Expand the inclusion and exclusion inputs.

[praveen12bnitt]

In our project, we had to exclude a lot of generated files. These generated files are specific to each project. So we decided to have a properties file in each repository, which will have the list of generated class files name. This file will be loaded by EnvInject Plugin to set the property in the build context.

In the jacoco plugin configuration, we will use the env variable like this ${JACOCO_EXLUDE_FILES}.

This PR will make sure, the jacoco plugin expands the variable before using it.

[pmv]

We have a similar use case, but would like to have the threshold numbers expanded. Not sure if that would be easy to add to this pull request or if I should create my own pull request.

[drwoods]

We could use this feature too, but would also like to use build parameters for the paths to Exec, Class and Source dirs, so we can parameterize our Job DSL generated builds.
+1 on the current commit

[centic9]

Please provide separate PRs for additional expansions that you would like to make use of.