remove e4x
remove experimental code
template-tag.js: support Components.utils.import
use firefox's template literal(>=Fx35)
fix: broken muttator compose window
fix: broken StatusField.prototype.init
fix comment about es6-template
Check if firstHint is null in hints.js

When hints are opened and closed too quickly it throws
'TypeError: this._tabNavigation[firstHint] is undefined'.

Can be reproduced by hitting f followed by <Esc>.
Merge pull request #100 from tarjoilija/dev

Check if firstHint is null in hints.js
Merge pull request #102 from caisui/fix/template

Fix/template
update tutorial
Merge pull request #103 from chenxsan/update-help-file

Updated tutorial