Make narrowWideReferences its own pass.
Dereference widenMap at the call site.
Update compilerPerformance.perfkeys with new pass.
Merge remote-tracking branch 'upstream/master'
io: add function isDir

This function will check whether the given path is a directory.
io: add isFile

This function will check whether the given path is a regular file.
Catching up on past 6 weeks regressions...
Add a multilocale test for chdir/cwd().

Suggested by Michael.  Multi-task one is next.
Update the comments on chdir and cwd to represent their behavior in multilocale
situations.
Merge branch 'master' of https://github.com/chapel-lang/chapel
Tuesday afternoon REGRESSIONS snapshot
Updating description of walk#9 failure
Add a test to lock in the behavior of chdir and cwd in a parallel environment.
add error checking on number of captures
add error checking on overflow in allocation for MAYBE_STACK_ALLOC
Add a README for the runtime unit test hierarchy.
Merge branch 'master' into multilocaleChdirTesting
Merge pull request #459 from gbtitus/test-runtime-README

Add a README for the runtime unit test hierarchy.

Not reviewed.
Merge branch 'master' of https://github.com/chapel-lang/chapel into triage-sep-blc
support octal in writef/readf