Implements tasks for creating and deleting new sessions, and allows
terminal handler agents to distinguish between sessions.
Includes bits of preparation in drum to more fully support multiple
distinct sessions, but doesn't get it all the way there just yet.
Gall would send %onto gifts to notify about app updates and update
failures. This would end up in dill, which printed some appropriate
text.
Here, we make gall responsible for doing this printing itself (by
having it explicitly ask dill to print some tape/tank), instead of
relying on the receiving end of some bespoke notification protocol.
Previously, we relied on foolish hacks, like [%met %bac], to send
"special" keystrokes with modifiers.
This updates the belt type to have %key, which represents a single
keystroke, with any combination of modifier keys.
Note that this has overlap with %txt to some extent. [%key ~ 'a'] should
be considered equivalent and preferred to [%txt 'a' ~], but updating
existing usage is left to a later commit.
The subscription changes in drum broke existing subscriptions. This
worked alright (though loud) for dojo, but it left chat-cli "frozen"
unless you manually unlinked/relinked. This does that automatically.
It also includes a refactoring of +on-load in drum, to avoid vain
repetition.
OTAs commonly end up in an inconsistent state if apps depend on changes
to /sys. For example, the %sift changes break on OTA because %spider
needs to be reloaded so that it's aware of the new thread type. This
adds a %goad app, which reloads all apps after every change to /sys.
Getting this to start OTA is nontrivial, but this pattern should work
for apps in the future. The changes to clock shouldn't generally be
necessary; they are only necessary here because we can't rely on hood to
start goad, since hood fails to compile if it's run before zuse is
reloaded. Once goad is active, this will cease to be a problem.
