Save progress on exists functions.

Added a test and the basic set up for the exists function.  Have not implemented
it fully, so it will not compile correctly.  Saving progress so I can work on
bug fix week.
Progress as of yesterday.
Merge branch 'master' into exists

Make sure it is up to date with trunk.
Finish backend support of exists.  Also minor bug in the module code where
I had forgotten to pass along the filename from the error-throwing function to
the error-returning function.
Forgot a new line, again.
Merge branch 'master' into exists
Adding a case to the test: the link exists, but is broken.
Check that err is not equal to the no error case, instead of that it is 0.

It's better to use the interface values in case they change in the future under
the covers.
Switch occurrences "if err" to "if err != ENOERR".

Greg had pointed out in his review of my patch for the function exists() that it
is better to use the interface instead of assuming that 0 means there is no
error.  Fixing this in other places.
Merge pull request #655 from lydia-duncan/exists

Add exists() function [reviewed by gbtitus]

Implements the function exists, which can be called on a given path
name. If the given path does not exist, will return false. If an error
was encountered, will inform the user of the error. If both of these
cases are false, will return true (for the file exists).

This function is implemented in runtime code, in the file chpl-file-utils.c
and is called through a module interface found in FileSystem.chpl.
I added the test test/io/lydia/exists/fileOrDirExists.chpl, which tests
correct behavior when the file does not exist, when a file or directory
exists, and that a link to either passes.
Re-add logdirs in whitebox scripts.

These scripts do not source common.bash, so it is not set by default. They were
accidentally removed in c2c3e9b.
Add narrowWideReferences to .graph files

Generate narrowWideReferences as part of the compiler performance graphs (the
data is already being collected for the pass)
Swap order of LICM in .graph files

LICM was moved to run before prune2 a while back, I updated the .dat and
.perfkey order, but never changed it in the .graph files. The order doesn't
really matter but it's nice to have it in the same order that the passes run.
Merge pull request #657 from lydia-duncan/fixErrorComparisons

Switch occurrences "if err" to "if err != ENOERR". [not reviewed]

Greg had pointed out in his review of my patch for the function exists() that it
is better to use the interface instead of assuming that 0 means there is no
error. Fixing this in other places.
Merge pull request #656 from ronawho/fix-comp-perf-dat-files

Add narrowWideReferences to .graph files

[trivial, not reviewed]

Generate narrowWideReferences as part of the compiler performance graphs (the
data is already being collected for the pass)
Use Nightly to keep track of whitebox logs.
Merge pull request #658 from thomasvandoren/fix-wb-log-dir

Re-add logdirs in whitebox scripts.

These scripts do not source common.bash, so it is not set by default. They were
accidentally removed in c2c3e9b.