- Fixed error "ICE plugin init: TypeError: sel.nativeSelection is nul…

[ZhenyaP]

• Fixed error "ICE plugin init: TypeError: sel.nativeSelection is null" on loading CKEditor
• Reworked demo.js to initially set ckeditor data to value which helps to reproduce the bug "'ice.dom.remove is not a function' error occurs when clicking on 1. Ctrl+A, 2. Del buttons on ckeditor control"
• Fixed 'ice.dom.remove is not a function' error when clicking on 1. Ctrl+A, 2. Del buttons on ckeditor control

[ZhenyaP]

Hello, everyone! On this commit I fixed the following issues:

1. When ckeditor control (with enabled change tracking functionality) is initially loaded with data that contains non-applied changes (like this: "<p>Add or delete text to unleash the power of the <strong>Track Changes CKEditor Plugin</strong>.</p><p><ins class="ice-cts-1 ice-ins" data-changedata="" data-cid="2" data-last-change-time="1502268617909" data-time="1502268615033" data-userid="18" data-username="Roger">This is Roger</ins></p>"), then (steps to reproduce bug): 1). Select all content of the ckeditor by pressing Ctrl+A shortcut 2). Try to remove all content by pressing Del button Actual Result: the javascript error "'ice.dom.remove' is not a function" occurs, which is thrown in ice.js

2. When loading ckeditor control, the javascript error "ICE plugin init: TypeError: sel.nativeSelection is null" occurs, which is thrown in the rangy-core.js