Feature request: inline way of telling clonedigger to skip parts of code

There is the --func-prefixes option but it's not flexible enough. I'd rather want clonedigger to be also able to do what other code analysis tools (pylint, coverage) can - skip explicitly marked parts of code.

For example something like:

```
def foo():  # clonedigger: skip
```

would skip the function foo()

Or

```
class Bar:  # clonedigger: skip
```

would skip the whole class Bar
