Added support of other configurations

[migiger]

This pull request includes the support of different configurations that can be added to the verify process. If no additional configurations are added, the plugin still only verifies the compile configuration. To add other configurations just use the following code block:

// Example: Add testCompile configuration to the verification
dependencyVerification {
   includedConfigurations += [configurations.testCompile]
}

The calculateChecksums task will now also calculate the checksums for the test dependencies. Since many projects also include at least tests, I think this is an absolutley necessary extension for this plugin.