#1371 "add files" dialog should preserve import dialog options

[Daniel DeLorme]

When selecting "Add files" on a node, the import options are always set to the default values, namely:
Traverse directories: ON
Add hidden files: OFF
Flatten file paths: OFF
Keep Project Tree: ON

The Keep Project Tree default value is especially inconvenient, as it will create (and insert the file in) a different node than the one from which "Add files" was selected if that node didn't follow the file hierarchy. I have to unselect "Keep Project Tree" every single time I want to add files. Possible improvements:
a) default "Keep Project Tree" to OFF
b) preserve the import options used the last time a file was added
c) add default import options in the plugin's options

[Alan Ezust]

moving to plugin bugs. This is not a feature request, but a bug.