Unify behavior of mode bits for files/directories.

Previously the prescribed behavior by chirp_reli.h mandated that only the user
executable bit could be set. However, the chirp_fs_local.c implementation
allowed setting group/other bits and the executable bit can only be changed if
the file is not a directory.

This commit explicitly documents the user may set group/other bits and the user
executable bit (for non-directories). All backend file systems implement this
except HDFS, which has no executable bit.
Set glibc variables tracking the program name.

This also affects /proc/pid/cmdline.

I think another way to do this is Linux prctl and POSIX pthread_setname_np
(which on Linux wraps prctl). However, there are two problems: (1) prctl limits
the length to 16 characters including the NUL terminator and (2) not all
utilities read /proc/pid/comm (which prctl changes). It seems most utilities
prefer /proc/pid/cmdline which is based off of argv[0]. How it is actually
changed is not very clear. These glibc variables appear to affect it.

setproctitle (BSD, but also on Linux) is another way to change the title.
fix: use allocated in worker to check task fit
fix: add committed, not inuse
Count resources only at intervals.

By including inuse in resources, local_resources changes very rapidly,
and for each change the master receives a resource update.

This commit makes it so that resources are sent to the master at no less
than the resources interval.
Log on tag, not on cores.
Remove double debug message (use one from wq_resources.c)
Merge pull request #435 from btovar/small_fixes_for_local_resources

Small fixes for local resources
Disconnect if no waiting task at the worker can be executed
Comment about short/long-term solutions
Fix compilation of WQ bindings.

If we link against systemd, compilation would fail.
map off_t to int

Fixes #437.
Merge pull request #434 from batrick/glibc-process-title

Set glibc variables tracking the program name.
Merge pull request #438 from batrick/wq-off_t

WQ bindings handles off_t
Minor change to prevent phantom error.
Check fd is valid.
Add test for mmap using Parrot fd unnecessarily.
whitespace
Allow Parrot to close unneeded mmap fd.

If Parrot does not need to write through any changes to the mmap region, we
close the fd to free up the slot in the kernel table for Parrot.

Fixes #431.
Check fd is writable.