support for wildcards (glob) in exclude

Currently, only real paths are allowed. This would allow to exclude paths like `/home/project/plugin/*/integration-tests`.

**Example**

This would allow us to define testsuites as follows

```
   <testsuite name="SystemTests">
        <directory>./System</directory>
        <directory>../../plugins/*/tests</directory>
        <directory>../../plugins/*/Test</directory>
        <exclude>../../plugins/*/tests/Integration</exclude>
        <exclude>../../plugins/*/Test/Integration</exclude>
        <exclude>../../plugins/*/tests/Unit</exclude>
        <exclude>../../plugins/*/Test/Unit</exclude>
    </testsuite>
    <testsuite name="IntegrationTests">
        <directory>./Integration</directory>
        <directory>../../plugins/*/tests/Integration</directory>
        <directory>../../plugins/*/Test/Integration</directory>
    </testsuite>
    <testsuite name="UnitTests">
        <directory>./Unit</directory>
        <directory>../../plugins/*/tests/Unit</directory>
        <directory>../../plugins/*/Test/Unit</directory>
    </testsuite>
```

Basically, in `SystemTests` we want to run all tests that were not grouped into Unit or Integration tests as plugins might not follow guidelines to put them into a Unit or Integration directory and to stay backwards compatibility. We would maybe even create a new suite for uncategorized tests or something similar.