Incorporated (and tweaked) your features

Hello Rutger, thanks for the pull request. I merged it, then reworked the functionality to mirror the rest of the API.

- The name of the pulsar is just psr.name
- Now the list of unique flags is returned by psr.allflags. I am also cutting out the dash at the beginning of the flag name.
- The values of the individual flags are available in, e.g., psr.flags['chanid'].
- Both the names and values are read and stored at initialization.

What do you think?

Michele