A logic issue existed when validating whether a `cl::opt<T>`
was set. This has been addressed by replacing `isDefaultOption`
method with `getNumOccurrences`, as the former one was not
meant to be used for checking if the option was set or not.
Likewise, the default Option itself is written to a `std::string`,
in method `get`; the latter is leveraged by `Invokable`.
Add additional field MIMEType to Container.
This allows API consumers to know at runtime how to treat the data
within a container without any prior knowledge.
This commit imports all the revng pipes (and other support utilities) to
be used with `revng-pipeline`. In particular, the pipes necessary for
binary translations have been introduced.
Alessandro Di Federico