Return quality flags depending on fields requested

[torimcd]

There are both overall quality flags (eg reach_q, node_q) and individual variable quality flags. We should consider automatically returning the associated quality flags for when fields are requested that have them, to help ensure users are interpreting the data correctly.

We could:

• always only return the overall quality flags
• only return the associated quality flags for the specific fields requested
• both?

[cassienickles]

I'd say return both! Good catch :) And when the bitwise explanations for the quality flags are present, we should return those too. (e.g., reach_q_b associated with reach_q)