write_raws for individual banks

[zhaozhiwen]

in code banks/src/evio2root.cc, "write_raws" will turn on raws bank entries like "pid,mpid,..." for all banks and by default it's on
This create a lot of entries in all banks.
generally flux bank wants those entries to show information, but any customized banks may not want those.
It's better to be able to turn on/off those entries for each bank individually.
The desired default behavior is on for flux and off for any other banks.

[zhaozhiwen]

INTEGRATEDRAW is enough for gemc because it can control individual bank

SELECT_RAW_VARiABLES in eveio2root is cool.
I think it allows us, as an example, to output "pid", but not "mpid"
But it doesn't solve the problem

for eveio2root, I think the prefer solution is from 1 to 3

1. translate all banks in evio as it is into root
2. use option "write_raws" to control individual bank, so that it can mimic what I set INTEGRATEDRAW when running gemc to produce evio
3. make default behavior to output flux trueinfo, but not any other banks. this works when I set INTEGRATEDRAW="flux" when running gemc to produce evio