gtk: within_margin should be a double.
seq: add document sequence to track unsaved file number
GbTabStack: add stack container for new style tabs
build: add doc sequence to build
GbTabGrid: add tab grid for grids of GbTab
vim: add jump-to-doc signal for SHIFT+K
vim: ignore mark_set() if we are not the focused widget
vim: use connect_object() for object lifetype tracking
vim: don't capture Escape so snippets can handle the signal
tab: use single bit for boolean
tab: add controls child for tabs
menus: add menus for GbTabStack
keybindings: add keybindings for tab movements.
keybindings: update keybindings for new tab design
build: add gb-tab-stack.ui to build
css: update window styling for new tab design
build: remove legacy files from build
document: move change monitor and code assistance into GbEditorDocument
markdown: add markdown preview as self contained tab
devhelp: use devhelp assistant for document tab

We'll have some more documentation types soon, but this gets us started