Object naming and dry run

Object names are now generated as specified in #132 (currently stored on the measure3 directory).  Also added a --dry-run option.
Note that in order to maintain consistency, the object counter is incremented as soon as you read it to generate your source name.  Otherwise two people could read the value and get sources with the same name.  Also, there is a count of 2 for one of the epoch/fields left over from my testing, but VOSpace seems to be offline at the moment so I can't clear it.  Will do that tomorrow.