blobserver/google/cloudstorage: add optional in-memory Fetch cache

So blobpacked can get blobs quickly without HTTP GET requests when it needs
to do all the small blob fetches when writing the zip file.

Change-Id: Ibbab0483920f2ef3b70c60eeebcd0056a8e4364f
Fix 32-bit builds.

Change-Id: I84c361dc442070802222e33df744876453cb43d3
fix SetShareSearch doc

Change-Id: I751b3b209f974830960480460e14c811ee9a5617
third_party: cleanup imports.

I think these snuck in because not everyone has the client side git
hooks registered to check on misc/review.
Removed third_party/github.com/bradfitz/latlong/gen_test.go (per
review feedback)

Change-Id: Ide09d152b28157a043009d7285f1afd4a60ac9de
Merge "third_party: cleanup imports."
Merge branch 'master' of https://camlistore.googlesource.com/camlistore
make.go: tags list should be space-separated

Change-Id: I8c50a2cc0fb293644467813b53606ed09faf6fc9
indexer: images: try a FileReader if the prefix is too small for DecodeConfig

Go's image.DecodeConfig needs more than 1MiB on some images (e.g. some
Lens Blur pics taken with Google Camera). Now we first try a 512KiB header
and retry with a full FileReader if that fails.

https://camlistore.org/bugs/477

Change-Id: I286d15d86a69951737d94dd3692d4e9e1992b324
index/receive: address last comments from http://camlistore.org/r/3271

Change-Id: Id41278e5e01b9ea9310b392859709a3261dc3f52
index: avoid shadowing err when retrying to index a full file

Change-Id: Ie683739039116dfb2758c6647382afebaa6e1ece
Merge branch 'master' of https://camlistore.googlesource.com/camlistore
blobpacked: temporarily rename StreamBlobs away so it doesn't implement BlobStreamer

Change-Id: I7906cb60b85d553fcb6632305164acabbc37e72d
blobpacked: don't declare ourselves as a BlobStreamer yet

Change-Id: Ie030e640a614a4dfa8b3afb3b30498eba2e3293d
blobpacked: update RemoveBlobs TODO with a plan

Change-Id: Ic89c390c15adba96333d3d20795b8bcc204e20f8
blobserver/google/cloudstorage: make it a SubFetcher

For blobpacked.

Change-Id: Ibca3d8a6976d8e1d4058e8d7fcdca6b63f8d8b87