First draft of codespeedization of test/perf

* Change webhook notification URLs to julia.mit.edu (Linux) and criid.ee.washington.edu (OSX)
* Add `codespeed` target to test/perf/Makefile, which will run perfsuite and upload result to hardcoded codespeed installation location
  * Note that `make codespeed` will attempt to `Pkg.add()` the packages `JSON` and `Curl` if not already installed.
  * The sort subtests run a limited subset of 28 tests instead of almost 800
* Annotate all @time macro calls with an extra "Description" field, used to populate the codespeed database for the first time
* Until extra build-time information is provided, expect environment variables such as JULIA_FLAVOR, JULIA_BRANCH, and JULIA_COMMIT_DATE on the command line when `make codespeed` is invoked.
`@allocated`: back to version that uses a thunk.

This attempts to avoid allocation by wrapping the expression to be
called in a thunk. This is somewhat unsatisfactory, however:

  - the code does not behave as it would in the current context
  - compilation may still occur during function execution

Still, this seems to make @timholy happier :-)
Revert "Revert "Update to openblas 0.2.7""

This reverts commit c9a7206b0ef87dddb8091b99dff168f27d78f307.
fix #2838, helps with #2597
Merge pull request #3813 from JuliaLang/sf/perfcodespeed

First draft of codespeedization of test/perf
Merge branch 'master' of github.com:JuliaLang/julia
Only run kernel/micro/shootout on codespeed
rewrite ``indexin`` function according to @timholy and using comprehension

rename to indexin

rename to indexin
Merge pull request #3269 from wlbksy/master

Add ``indexin``, which is similar to Matlab's ``ismember``
Merge github.com:JuliaLang/julia