paket outdated should optionally evaluate version constraints

[agross]

Just like in bundler, I'd like to see a --strict option to enable listing outdated packages w.r.t. the version constraints in paket.dependencies.

[forki]

so --strict would be the mode we are currently running.
In the new default mode we would assume no version requirements are given in dependencies file and basically all is >= 0!?

How does this relate to #184?

[agross]

paket.dependencies:

nuget Foo ~> 1.2 prerelease
nuget Bar ~> 1.2

paket outdated:

• check for new versions of Foo, 0 <= x
• check for new versions of Bar, 0 <= x

paket outdated --strict

• check for new versions of Foo, 1.2 <= x < 2, including all prereleases
• check for new versions of Bar, 1.2 <= x < 2

paket outdated --pre

• check for new versions of Foo, 0 <= x, including all prereleases
• check for new versions of Bar, 0 <= x, including all prereleases

paket outdated --strict --pre

• check for new versions of Foo, 1.2 <= x < 2, including all prereleases
• check for new versions of Bar, 1.2 <= x < 2, including all prereleases