clarify om.core/root app state invariant
OM-80: disallow cursor deref during render phase
OM-86: IRenderState bug

assumed state is set, change IInitState so all components get at least
empty hash-map for initial state.
OM-86: IInitState bug, do not attempt to call render ourselves

Trying to call render ourselves breaks React
OM-88: seq on empty map cursor returns lazy seq
remove om.core/join
OM-89: subtle set state bug on inputs
breakout IValue protocol. You can now build components from anything not
just cursors. Change om.core/graft so that what we return is the original
value that's been specified so that state changes work. Throw a error if
a app state transition is attempted. Throw an error if given an existing
cursor for the value. Update the graft example to verify that locate
state stuff still works, but also that embedding a cursor also works.
add missing index.html change
0.3.1-SNAPSHOT
OM-90: broken graft example
0.3.1
next dev cycle