Version 0.2.x of the "time" crate comes with an API that is quite
different from version 0.1.x. This commit upgrades Inko to this new AP.
As version 0.2.x does not support checking if DST is active, support for
this has been removed. DST support is tricky, as it can vary based on
where you are, politics (e.g. some countries may drop it), etc.

As part of upgrading to time 0.2.x, some of the internals for obtaining
timestamps has been changed. In particular, obtaining a timestamp and
UTC offset has been merged into a single VM instruction. This should
ensure that no funny business happens when obtaining a timestamp but not
obtaining the UTC offset until a later point in time. The downside is
having to allocate an array object, but the overhead of this should be
minor.

This fixes #188