Along with this, Port.h is include which helps generalising common
information for the port package, like it's name and version. With
SemVer complaint versions, it is possible to show positive change
(upgrade) or negative change (downgrade) in the installed ports.
However, for some non-complaint versions (eg. using git commit hash),
non-equality (`!=`) is used to notify upgrade. Since there is no
algorithm (without git history) to check the order of commits, it is
not possible to inform whether it is an upgrade or downgrade.
The "dependency" lines really belong to the main port entry, it doesn't
make sense logically to represent them separately and handling them
together will also allow easier dependency management later on. This
commit greatly simplifies the port database parsing to facilitate this,
and removes the -d option from the command line. Instead, ports are
listed with their dependencies, if they have any.
