schema: integrate with the jsonsign package.

Signing schema blobs (permanodes and claims) was too hard before, and
the code was scattered in weird places.

The pkg/jsonsign code tries pretty hard to be Camlistore-neutral, so
it remains so.

The pkg/client code (which deals mostly with HTTP access to a remote
camlistore server) had the signing the logic in it before, mostly
because that's where we originally needed it (for camput), but that
should be fixed in subsequent changes, to remove most of its signing
logic and use pkg/schema's instead.

The schema package now depends on jsonsign, which I think is an
acceptable dependency edge, since the Camlistore schema does logically
depend no signed claims (and that was a gaping hole in its public
API), and it seems safe cyclic-wise, especially if jsonsign continues
to be a leaf package.

Change-Id: I10229ec5d880ddd801cb1ba77ac26b654693036d
client: use the schema.Signer API, remove Client.SignBlob method

Change-Id: I177c78f4f7f4ca54afd021d4ada866a35eea06eb
Add new pkg/client/android, to clean up Android API gunk from pkg/client's godoc.

This is just a start. AndroidStatsTransport and AndroidStatusReceiver and most (all?)
of pkg/client/android.go should migrate too.

Change-Id: Id4140730bbdd218fdf7ba7cedc7870ce5164e06c
Add camtool to devcam.

Change-Id: Ife10222ca8f1ba08be923f9433781910376ddf05
Merge "Add camtool to devcam."
devcam: fix up package doc strings

Change-Id: I5f1b85e872a2d66d3c68babd2a2b53b76fb23dc3
Merge "devcam: fix up package doc strings"
importer: start of RootObject method and SetAttr

Change-Id: I2cc64e259a5c377595d719e6eb0df1b41d83d679
Merge branch 'master' of https://camlistore.googlesource.com/camlistore
Merge remote-tracking branch 'upstream/master'