Add licence, change argumbnt handling to alway recognise '-' as
	a flag prefix, make a little easier to expand to other algorithms
	in the future, and change file handling.  Previously a misspelt
	passphrase could destroy existing security data (i.e., '-c'
	would leave an empty file rather than whatever had been there
	before).  Also distinguish between failure causes in the
	exit status.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/1.3.x@82898 13f79535-47bb-0310-9956-ffa450edef68