Create symlink to `allpairs_multicore`

Without this the prepare step of both allpairs tests fail on OS X with 'allpairs_multicore not in path' error.
New method for allpairs test.

Check that each input file occurs n times (where n is the total number of input files) in the first two columns of the output, which is the expected pattern for an allpairs run.
remove 'horrible, horrible' testing method
remove makeflowlog generated during testing
Merge pull request #5 from rampantmonkey/test_cleanup

Test cleanup for bitwise allpairs.
The code that handles sending input files is now refactored into 4 functions:
1. put_input_item() which replaces put_file() from before
2. put_directory() which sends mkdir() to worker and sends its contents by
calling (recursively) put_directory() or put_file()
3. put_file_whole() which sends the entire file contents to worker
4. put_file_piece() which sends the file contents within specified byte offsets.

This fixes Bug 993: Cached and Uncached directories in work_queue_worker.
Memory maps io test with getrusage memory faults.
Adds FreeBSD monitoring of memory and cpu time.

Monitoring for FreeBSD is now only missing bytes read and bytes written.
Adds comments dag_node.
Replaces # SYMBOL with task categories.
Added support for password authentication between master and worker.
Updated copyright boilerplate.
Combined all uses of srand into a common random_init().
Changed all isntances of srand to random_init().
Small fixes for work queue authentication.

- Added -P as an option to work_queue_worker to indicate the password
  file.
- Updated documentation to make clear the difference between the
  password file and the password itself.
- copy_file_to_buffer behaves like other functions in copy_stream.
Remove debugging fprintf from copy_file_to_buffer.
Added docs for the simple group management feature.
Fixed incorrect function name in example.
Added work_queue:specify_password_file() and updated docs to demonstrate it.
Added hash_table_clear() as a counterpart to itable_clear().