Bug 923048 - Use document.createDocumentFragment. r=stas

Use document.createDocumentFragment in place of new DocumentFragment(). The
constructor is not supported in IE & Safari.
Bug 918655 - Get rid of getComplexString; r=stas
follow up - unbreak jshint tests
Bug 923552 - shell:perf results affected by process dots. r=gandalf
Bug 923461 - Clean up the start-up logic. r=gandalf
Bug 923547 - Delay array/objects initialization in compiler; r=stas