style(Observable tests): "Observable instance" > "Observable"

There're no separate tests for the class, so why "instance"?
refactor(Component tests): remove unnecessary tests

Other tests will fail anyway when something checked in these is wrong.
feat(gulpfile): don't use bail: true for Mocha

Sometimes tests run not in the preferred order: you want to fix X,
but Y fails first and you can't see the call stack for X.
Let's remove bail: true.
refactor(Component): extend from Observable
docs(Component): remove excess docs
refactor(Component): use isInited() instead of inited

Keep inited (bool) in @_component_inited, use isInited as getter.
This keeps from unwanted state changes.

Also throw when trying to init when already inited.
refactor(Observable): _listeners > _observable_listeners

Prefix private field _listeners with class name.
This saves from name collisions. Now child classes can use _listeners.
fix(Application tests): fix tests to meet changes in Component