Add option --recheck-file-creation.

To handle NFS semantics, this option tells makeflow not to fail
if a file from a succesful job is not immeditely available. Makeflow
retries for the file before failing.
Allow user to set tries/wait time
Merge pull request #647 from btovar/patience_nfs

Add option --recheck-file-creation.
Added all: target so default make does nothing with apps
Merge pull request #649 from nhazekam/apps_make

Added all: target so default make does nothing with apps
Simplifies recheck option for NFS.

I don't know what I was thinking. Simplifying from three command line
switches to one. Now use:

--wait-for-files-upto=<n>

to wait upto n seconds for files to appear at the filesystem running
makeflow.
Add --no-set-foreground option to parrot to execute the tracee in the background.

Currently, parrot allows the tracee to set its process group ID to its own PID and
set its process group as the foreground process group of the session by default,
which may break the program which first calls parrot and then needs to use
terminal (to use terminal, the program must be in the foregroud process group).
Merge remote-tracking branch 'ccl/pull/651/head'

* ccl/pull/651/head:
  Add --no-set-foreground option to parrot to execute the tracee in the background.