Flat Extraction Feature

[mega5800]

:+1::tada: First off, thanks for taking the time to contribute! :tada::+1:

Please fill out the following checklist:

• [ ] Added tests for any bug fixes that changed existing code
• [ ] Added tests for any new behavior
• [ ] All unit tests are passing (please make sure all tests are passing for your branch/PR at https://ci.appveyor.com/project/activescott/lessmsi/history )

If you need any help at all, feel free to submit the PR and @-mention activescott and I'll be happy to assist!

Hello @activescott

I took care of this ticket.

I added new CLI commands "xfo" and "xfr". "xfo" allows the user to flat extract MSI files while overwriting files with the same name. "xfr" allows the user to flat extract MSI files while renaming files with the same name using the suffix "_" with a count.

As discussed, I experienced a few issues with creating test files for this new behaviour. So I am sending this PR as you suggested.

Please let me know if you have any questions.

Thank you.