rockspecs: add 0.8-1

Added tag 0.8 for changeset e11df013b0a0

docs: expand release notes, prepare for 0.8, add todo/milestones section

docs: tiny rewording

docs: mention examples/ and spec/

hglib: transform input into a string (for writing)

hglib: handle cases when user didn't provide any input

spec: test runcommand_co()

docs: missing ticks

hglib: make inner loop in runcommand() use a coroutine Then it's possible to do something nontrivial using the more low-level client.runcommand_co().