FileStorageModel mishandles delta=6 qualifier

[jbfaden]

The following Autoplot script demos where the delta=6 qualifier is mishandled in Das2, causing Autoplot to load two files when only one was needed, and thus running out of memory. $(H;delta=6) should imply 06:00 to 12:00, not 10:00 to 16:00.

setScriptDescription('''This demos where the FileStorageModel mishandles delta.''')

from org.das2.util.filesystem import FileSystem
from org.das2.fsm import FileStorageModel
fsm= FileStorageModel.create(FileSystem.create('file:/tmp/jbf'),'$Y$m$d_$(H;delta=6)')
print fsm.quantize(datumRange('2021-01-17T10:49 to 2021-01-17T10:50'))
print '2021-01-17 06:00 to 12:00 it should be'

[jbfaden]

The FileStorageModel uses TimeParser to implement the times, which wasn't looking for delta, but did support "span". "delta" is the term we agreed on for the URI_Templates, and this should be supported as well.

Note the TimeParser does not faithfully implement URI_Templates, since it preceded URI_Templates. It needs to be updated to completely support URI_Templates (probably using the URI_Templates library https://github.com/hapi-server/uri-templates).

I've made it support delta in this case.