make: only build binaries and their dependencies.

New behavior for -targets:
- Empty only builds default binaries for this requested platform.
- * builds binaries and recursively builds pkg/..., server/..., and
    third_party/... (old empty behavior).
- Or specify the packages you want to build separated by commas.

This should fix the failing build on FreeBSD.

Change-Id: I3e19fd26b7fa5526bb2139487f25a07fa01952c4
Merge "make: only build binaries and their dependencies."
camput: limit upload concurrency (number of goroutines)

Use separate workers for directory uploads.
Limit upload concurrency to 3+2+3 (normal+directories+stat)
goroutines on Android, and 10+5+10 otherwise.

Thanks to the predictably failing test (1333551)
which we can test against, we can eliminate the need for
unbounded number of upload goroutines (see ee4550b).

Change-Id: Idac4c94b7d7ec4fc6c6a77fed111e0ece0843545
make: add cammount to default targets.

Fixes default build on Linux (and probably Darwin).

Change-Id: Ice9e4cfbcde2b565c7f084c5cac57468bea08165
Getting started with 0.7 release notes.

Change-Id: I23dae7c1219c2632d2e0a505699631058a7b4163
Merge "Getting started with 0.7 release notes."
Merge "camput: limit upload concurrency (number of goroutines)"
camput: re-enable deadlock test, now that it's fixed

And tweak limits a bit lower.

Change-Id: I7a38ffce37a997aa6ce9943e13605e76476f5646