exp/locale/collate: preparation for adding Search API. Also changed the collate API
further to how (I believe) it will end up being.
It is nicer to separate search from sorting functionality. Collation needs tables that
are not needed by search and vice-versa.  The common functionality is separated out
in the Weigher interface.  As this interface is very low-level, it will be moved to
a sub package (colltab) in a next CL.
The types that will move to this package are Weigher, Elem, and Level.  The addition
of Elem allows for removing some of the duplicate code between collate and collate/build.
This CL also introduces some stubs for a higher-level API for options. The default
proposed options are quite complex and require the user to have a decent understanding
of Unicode collation.  The new options hide a lot of the complexity.

R=rsc
CC=golang-dev
https://codereview.appspot.com/7058051
exp/locale/collate: added functionality for sorting.
Eliminates the need for the user to fiddle with keys.

R=rsc
CC=golang-dev
https://codereview.appspot.com/7060051
crypto/x509: skip SystemRootsError test on Windows

On Windows, crypto/x509 passes through to Windows's CryptoAPI
to verify certificate chains. This method can't produce a
SystemRootsError, so make sure we always skip the test on
Windows.

This is needed because testVerify is called in both
TestGoVerify and TestSystemVerify on Windows - one is for
testing the Go verifier, the other one is for testing the
CryptoAPI verifier. The orignal CL tried to sidestep
this issue by setting systemSkip to true, but that only
affected TestSystemVerify.

R=golang-dev, agl, snaury, minux.ma
CC=golang-dev
https://codereview.appspot.com/7185043

Committer: Shenghou Ma <minux.ma@gmail.com>
go/types: typechecking conversions, part 1 (non-constants)

R=adonovan
CC=golang-dev
https://codereview.appspot.com/7103058
go/build: document blank line required after build constraints

Fixes issue 3539.

R=golang-dev, dave, adg
CC=golang-dev
https://codereview.appspot.com/7206049

Committer: Andrew Gerrand <adg@golang.org>
all: use t.Skip{,f}

Replace various t.Log{,f} ; return checks with t.Skip{,f}.

R=golang-dev, n13m3y3r, bradfitz, adg, mikioh.mikioh
CC=golang-dev
https://codereview.appspot.com/7193044
doc/go_spec: remove extra space, align tags, and change a tab to a space.

R=golang-dev, adg
CC=golang-dev
https://codereview.appspot.com/7198048

Committer: Andrew Gerrand <adg@golang.org>