also some cleanup and version bump to Q2

this prepares cache/txn structures to hold API as well, so we can get
rid of the global api

this allows for continuation of a function in the background,
a good use case for this is loading of chunks of data or I/O 

module api can now store userdata, e.g. owner

if the module declares such properties, they can be accessed
by treating module as a table, e.g.

hints[‘localhost’] = ‘127.0.0.1’
hints.hostname = ‘192.168.1.1.
print(hints.localhost)

equals to:
hints.set(‘localhost 127.0.0.1’)
hints.set(‘hostname 192.168.1.1’)
print(hints.get(‘localhost’))

extracted part about writing layers to lib documentation