Distinguish between two separate sub-tests.
Add a debug output to print the kdf in use, too.
Add coredump files to .gitignore
Huge overhaul. BROKEN COMPATIBILITY with old databases.

Seems stable, regression tests run.
Huge bunch of changes. Didn't worth splitting them up because they
depend on each other too much (except for a few...).
Here are the details:
- Remove 'random' command.
- Add 'tmux', 'xclip', 'Xclip' commands (get_line() and
  parse_newlines() functions are now back again from cmd_getnum.c to
  commands.c).
- 'passwd' command can now change KDF and cipher mode.
- 'xport' command can now specify KDF and cipher mode.
- 'import' command can now specify KDF and cipher mode.
- The 'new' command's first parameter, the key, now works with spaces.
- 'status' now shows the KDF.
- Introduce a 'struct db_parameters' type:
  This is used across the source to include some common stuff that
  correspond to the opened database instance (filename, iv, salt,
  etc... bunch of others)
  Also shortens some functions' parameter list, 'cause now we can just
  pass the db_params variable where needed, instead of passing iv, salt,
  cipher_mode, etc... .
- Bump IV and salt sizes to 64 bytes, and don't use just printable
  characters, use anything. IV_LEN and SALT_LEN only used when
  generating new values. IV/SALT_DIGEST_LEN is used where there are
  calculations with their lengths. (backwards incompatible change)
- IV/salt are now stored as SHA-512 hashes in the beginning of the
  database file, separated by newlines. (backwards incompatible change)
- get_random_str(): changed the last parameter's meaning. Now it's
  possible to get random "anything", not just printable or alnum.
- Try to zero out temporary key and pass values.
- Zero out key variable when exiting from the program.
- Don't check in main() the validity of 'kdf' or 'cipher_mode'. They are
  checked during kc_setup_crypt().
- Don't ftruncate() the database file before writing. Now the
  kc_setup_bio_chain() function opens the database file with readonly or
  write+truncate mode with BIO_new_file(), in light of the new 'write'
  variable's value.
- Change the project's URL from googlecode to github.
- Fix up regression tests after changes in the output while opening a
  database, new sample database and remove the cmd_random.sh test.
- Documentation and manual brought up to speed.