Deflag issues when using multiple flags with method='linear' or method='repeat'

[jameswilburlewis]

Deflag can accept multiple user-defined flag values passed in as a single array. If the 'linear' or 'repeat' methods are used with multiple flags,
a situation can arise where, due to a combination of flags, one or more slices through the data contain no unflagged values. But with these methods, deflag only processes one flag at a time, so it doesn't notice the issue if each individual flag leaves some valid data to work with.

For these methods, deflag should 'or' all the flags together for the individual flag values, before deciding whether to attempt to deflag that slice. (So the loop order needs to be inverted....outer loop for the slices, inner loop for the flag array).

This is probably a very uncommon situation, so not necessarily the highest priority....