rework attach to require explicit key
64k iterations plus pragma cipher_default_kdf_iter function
Merge branch 'prerelease' into attach
Merge branch 'prerelease' into kdfiter

Conflicts:
	src/crypto_impl.c
Merge remote-tracking branch 'origin/prerelease' into kdfiter
finalize new attach behavior

- key can be specified in hex as key plus salt together
- source passphrase is cleared after derivation
- key specification containing derived key and salt stored on
  cipher_ctx for use in attach on an encrypted main database
  when no key is provided with the attach statement
Initial work on a PRAGMA cipher_migrate

Swapping of the Btree meta data is not working properly now.
More work on cipher_migrate, still unusable
Swap btree for write, reset password on codec - working.
Clean up compiler warnings
Work to configure the proper env. for the migration
Attach new codec before btree copy
Add tests for cipher_migrate
null termination of key value
Adjustments to cipher_migrate

- And format flags when checking for exit condition
- Pass key size to sqlcipher_check_connection
- Trace version upgrade logic
Merge branch 'attach' into kdfiter

Conflicts:
	test/crypto.test
Bump cipher_version to 3.0.0
updates amalgamation script, but we'll probably have to drop it for Makefile
Merge branch 'prerelease' into Xcode5
Unlinks amalgamation target as dependency, run make to execute amalgamation by Makefile before building in Xcode