The event that triggers the package module to be activated is
now retriggered after the package module is initialized but without
any previously registered handlers. Instead only the handlers registered
by the package module will be triggered. The prior event handlers are then
restored after the event is retriggered.
This allows package modules to bind event handlers during initialization
that will be triggered by the same event that caused the package module
intialization to occur. This simplifies the common case of having the same
event cause a package module to initialize and attach.
Also, add a spec to cover the loading of keymaps in `atom-spec` and
reset the `keymap`'s internal data after each spec gets run to prevent
test pollution with keymaps.
The goal is that `loadPackage` will be the go-to place for loading all kinds of resources out of directories. `requireExtension` was only designed to load and activate extension modules.
