fix: javascript error on profile page [...]

The error appears when there is no component specific add forms (aka
composer forms) defined, i.e. only notes can be added from profile page.
It caused by the fact that in such a case element containing
ComposerTabs is replaced with empty content and subsequent calls of
el.getParent() return null. The fix requests for container element
during initialization and stores result in variable allowing referencing
to it even after initializing tag is removed.
upd: readme changelog