Invoke sudo on package-managing scripts

For testing purposes, this deals with between-command timeouts most
gracefully.  For instance, MacPorts should run on an up-to-date ports
tree, but port is network bound and could cause a later sudo to time
out waiting for someone to look at the screen again.
Correct script pointer
Fix OS X aclocal fixup check
Update gnulib pointer
Use output option of RE for evaluation test
Correct path
Potentially save a re-compilation in Centos
Log exit status of hivexml
Adjust usage notes
Guard xmllint check on Fiwalk output
Use absolute path to disk image

-o was encountering some issues after changing directory.
Abandon rdifference adaptation
Log errors from hive extraction
Add tally column for failed-hive cells
Abstract out a path
Document; expand environment variables check
Rewrite INSTALL
Revise README
Update deps distribution list
Add autotool checks to build script