All Primary datasets

incl. the changes discussed today, fake DOIs from Tibor's file, only missing 2 descriptions. Descriptions and other examples will follow tomorrow morning
Depends on the various data we shall store here (e.g. anything for Tools?) and on all the various use cases we shall make of them (e.g. any robots consuming these?).

(1) If we keep everything in one entry, e.g. `256 $a Data (N1 files, N2 events, N3 bytes)`, then the information will be well understandable, well stored and well preserved, but any automated tools would have to parse the text away in order to get to the numerical information.

(2) If we store the information in separate subfields, then clients could process it easily if we omit strings like "events"; but for long-term preservation we'll have to make sure this will be "remembered" N years from now.  For this, it might be nice if the master format itself contains something like `256 $e 25423849 $t evens` where `$t` stands for "text". 

In any case, if we split the information into separate subfields, then I suggest not to enumerate the information starting from `$a`, but rather use something sematically meaningful like `$e=events, $b=bytes, $f=files`.  The [MARC tag 256](http://www.loc.gov/marc/bibliographic/bd256.html) standard seems to have many subfields free.