Adds -V 'category: ...' to makeflow resource summaries.
Include limits set in the resource summary

The limits set are printed in the summary with the prefix "limits_".
This can be used to record what resources where requested, from which we
can compute an estimate of resources wasted.
Rewrite monitor command until the last moment

Now we keep separate the monitoring command from the original 'vanilla'
command, and rewrite the monitoring command just before the node is
dispatched to the batch interface.  This to allows the modification of
the monitoring command when resources are exceeded.
Read multiple summaries from stream

This allows to read multiple summaries from a single file, as they come
from the resource archive.
Monitor makeflow for all resources (not only disk and memory).
add option for controling the behaviour of explicit dependencies
long option for use explicit
move linker man page to makeflow_linker
add -e to man page
add -e to help display
make use_explicit a global option.

use_explicit was elevated to a global since it potentially affects every function.
allow explicit dependencies to be copied or skipped
add usage message
pass explicit dependency behavior to drivers
include option in test
add perl file type
list perl extensions
check for perl extension
first stab at perl driver
invoke perl driver for perl files