CanonicalHeaderKey didn't allocate, but it did use unnecessary
CPU in the hot path, deciding it didn't need to allocate.
I considered using constants for all these common header keys
but I didn't think it would be prettier. "Content-Length" looks
better than contentLength or hdrContentLength, etc.
R=golang-dev, dave
CC=golang-dev
https://golang.org/cl/6255053
This is Go 1 package renaming CL #3.
This one merely moves the source; the import strings will be
changed after the next weekly release.
This one moves pieces into net.
http -> net/http
http/cgi -> net/http/cgi
http/fcgi -> net/http/fcgi
http/pprof -> net/http/pprof
http/httptest -> net/http/httptest
mail -> net/mail
rpc -> net/rpc
rpc/jsonrpc -> net/rpc/jsonrpc
smtp -> net/smtp
url -> net/url
Also remove rand (now math/rand) from NOTEST - it has a test.
The only edits are in Makefiles and deps.bash.
R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/5335048
