The code base is growing much faster than expected, faster than Shotwell it seems (not necessarily line count, but files and necessary organization of the library vs. Shotwell's initial flat directory). After some thought decided to move to a more standard Vala/GTK naming scheme of all lowercase with dashes for spaces starting with namespace (minus the "geary-", unless the class was in the topmost namespace). Three motivations:
1. Often confusing when working on code to see three "Folder.vala" in the gedit tabs: one IMAP, one SQLite, and one the interface definition.
2. This paves the way for waf integration, as right now we're held up using it because it barfs on projects with two files of the same name in different directories.
3. I find the CamelCase in the file browser becoming hard on the eyes, and this scheme seems a little more browsable.
Much of the API between the local and net stores had to be reworked for consistency as well as planning ahead for how messages will be retrieved and stored efficiently. This work also attempts to keep in mind that other mail sources (POP, etc.) may be required in the future, and hopefully can be added without major rework.
This large diff represents a growth of the architecture to persist IMAP data as its downloaded. When listing folders, a local database is consulted first to immediately feed to the caller. In the background, network calls fetch the "real" list. The two are collated for differences which are reported to the caller via signals, who are then responsible for updating the user interface appropriately. No other synchronization work is represented in this diff.
Note that this breaks functionality: when a folder is selected, no messages appear in the message list. Fixing this requires more work, and this patch was already large enough. It's ticketed here: #3741
