Introduced non-root model for Storage (for caches)

Non-root storage is basically a cache that may provide some cached
state but is not a root of the update propagation tree (or DAG).
Some garlic, cross and silver bullets.

isRooted()/isUplinked() is too fragile and hard to derive.
!!_version is a much better criteria of statefullness.
0.3.11
fix: rename non-existing file
Timezone-independent epoch definition
refac: SharedWebStorage now extends Storage

+fixes +tests
KoaServer is rolled back; there is something wrong with koa-spa
Merge branch 'master' of github.com:gritzko/swarm
Clock normalization on Host handshake
Handling incorrect clocks at the clients
Corrected .init patch/state logic
fix: an amateurish callback avoidance bug
merge gritzko/master