Added force open in TextMate and fixed confusion when opening an alias.

Any file should be able to be opened within TextMate, so
Option-DblClick will always do that. I first noticed this with .xib
files.
Because of the order of the if statements, opening an alias to a
package or binary file (or .xib) would not have the previous if
statements applied to it.
Drop other expanded folders when revealing item

We probably should only drop expanded folders which descend from the current root, but that’s more code and the implemented behavior could be seen as “garbage collection” (keeping the memory of expanded folders low).
Handle untitled documents when filtering on path

These would previously be prefixed with the project folder path. Now they get no prefix (and disappear when the path-part of the filter string is non-empty).
Use command name as title for output windows

The command can set a custom title so this is only for commands that doesn’t do that.
Add xib and xsd as XML document types

The former is mainly to allow using Open With from inside TextMate (to force open the document with TextMate), as you likely have Xcode setup as the default app to handle xib files.
Going to SCM status has the groups expanded

Previously these would not initially be expanded but the expansion state remembered. Now that we regularly clear cache of expanded URLs, it’s more tedious regularly having to expand these two groups.

It also introduce new API for having data sources return what items should be initially expanded, which probably makes sense for some data sources.
QuickLook preview panel now zooms in/out
Tab bar collapsing now disabled by default
Position file chooser relative to text view

This is instead of placing it relative to the entire window. The main motivation is that with the file browser on the right, I want the file chooser closer to the left edge of the window.
Add helpers to create lines

With this we can create either a horizontal or vertical line, and don’t need to manually set a constraint for its width/height.
Use horizontal/vertical line creators
Add method to move focus to document or file browser
Add Navigate → Move Focus menu item

This has ⌥⌘⇥ as shortcut so should make it easier moving to file browser and back.
Fix “Go to Favorites” (wrong URL used)

The URL constant for the favorites location was setup using oak::application_support() but done before the app support folder was initialized (due to the setup function being marked as a constructor).
Add method for searching file browser folder
Fix missing open / modified status in file chooser

This only worked for untitled files since we no longer keep document UUIDs for documents with a path.
Use divider lines in root view

Previously we placed the views with a one point gap between them and had the superview fill the background. This works fine, but has the somewhat theoretical disadvantage that the superview then needs to implement drawRect: and for performance reasons declare that it is “opaque” which means subviews can’t use the (true) window background, should they want to.

Also add a preferences key for “tabs above document” (issue issue #214), but not hooked up in this commit.
Tab bar above document option

This change adds new option for showing tab bar only above document, so the
file browser header lines up with tab bar.

File browser header height reduced by 1 pixel to match tab bar height. It also
draws optional top divider when in same line as tab bar
Initial divider colors were wrong for inactive windows
Add bug tracking ID annotation