- Add disk-changer to scripts directory + configure/Makefile

- Add disk-changer to scripts directory + configure/Makefile
- Eliminate PoolId from jcr -- it is in jcr->jr.PoolId
- Implement store_bit scanner to replace store_yesno.  Mostly done.
- Implement new store_bool that stores in a bool.
- Add true/false to yes/no conf directives.
- Make first cut at changing appropriate store_yesno to store_bool.
- Complete implementation of Pool storage devices.
- Move starting clones to job.c
- Move create_restore_bootstrap_file() to job.c
- Make copy_storage() more general to be able to handle
  Pool storage.
- Cleanup a lot of migration code for manual running, including
  using Pool storage.
- Move getting a scratch Volume into a subroutine.
- Make all places a Volume that is added to a pool to
  respect max vols.
- Fix bug in autochanger recycle code (improper edit 64 bit).
- Fix segfault in restore command when no value specified.
- Start adding code to handle multiple MediaTypes in restore.
- Eliminate race condition in getting Volume name for
  two drive autochanger.
- More debug code in autochanger.
- Add storage keyword to bootstrap file, add parsing.
- Move slot in bsr file into Volume record as there will be
  a different slot for each Volume.
- Create reserve.h