Add the option to use tabs instead of spaces in pom snippets

[Hanno Embregts]

Not my intention to start a flame war here on tabs vs. spaces, but I noticed that the pom snippets use spaces for indentation:

❯ mcs search cocoon:cocoon-repository:2.1.11
Searching for cocoon:cocoon-repository:2.1.11...

    <dependency>
        <groupId>cocoon</groupId>
        <artifactId>cocoon-repository</artifactId>
        <version>2.1.11</version>
    </dependency>

It would be nice if the user could add an option to make the generated pom snippets use tabs for indentation:

-t, --use-tabs           Uses tabs instead of spaces for indentation in pom snippets

If you like the idea, I would be happy to contribute myself, by the way!