[RIS] Fix seriesEditor for reports and maps. Fixes #561
[RIS] Add configurable options for unknown field handling
- RIS.import.keepID: put ID field in note so that it's easier to fin item in EndNote. ID is now omitted by default.
- RIS.import.ignoreUnknown: do not store unknown or duplicate values in notes for a cleaner import. Overrides keepID. Notes are attached by default.
[RIS] Use file names as attachment titles. Determine mimeType from file extension. Addresses http://forums.zotero.org/discussion/5311?page=2#Item_27