Add stopApp function, for returning a value from runApp
Speed up selectInput when there are many choices
Speed up radioButtons when there are many choices
Add includeCSS and includeScript functions
includeText should be HTML escaped
Do away with dependsOnFile error

This error is causing more problems than it solves.
Expose session$input and session$output

This makes it possible for packaged Shiny components to only ask
for the session variable to get access to all inputs and outputs
(along with the other good stuff on session).
Add tagSetChildren() and tagAppendChildren()
Add tests for adding children
Add tests for creating nested tags
Refactor tag()

This is much faster when there are large lists of children (and the code is
much simpler!)
Fix handling of empty tags
Refactor checkboxGroupInput
Don't use named list items for selectInput and radioButtons

The names aren't used anyway, and this matches previous behavior (Shiny 0.6.0)
In tag functions, drop NULL attributes
Speed up input update functions
Export tagSetChildren and tagAppendChildren
Update shiny-package
Preserve attributes in child tags
Add tests for escaping in tags