move component

* This commit is only for arrangement of code.
* moves |naviTester| out of |mSiblingNavi| and renames to
  |NaviLinkTester|
remove obsolete function
rerwite string formatter to be simple
store data to node property instead of setting attribute

* stores a URL string or the reference of an <input> node
* defines |kID.data| as a property name for data store
* removes useless |kID.prefix| because we can find a valid target with
  the property in |onCommand|
* implements |onPopupHiding| to clear menu items that may have the
  reference to <input> in the content document
NaviLink: fix wrong string format
NaviLink: rearrange data hash for sibling scan
NaviLink: rewrite URI wrapper
NaviLink: create |getDocument()|
NaviLink: rename common constants
NaviLink: move local function to where it is used
NaviLink: rename some functions of modules
NaviLink: remove useless function
NaviLink: rename utility function
NaviLink: separate utility function
NaviLink: update description comments
NaviLink: minor cleanups

* No major changes
* update comments
* arrange formattings: braces, indents, new-lines, temporary local
  variables, and so on
NaviLink: rewrite function