Improvements to style handling in default Paste from Word filter

[Olek Nowodziński]

Following PR ​https://github.com/ckeditor/ckeditor-dev/pull/116.

---

In default filter's addStyle the following optimization is performed:

this.attributes.style = styleText.replace( /^;|;(?=;)/, '' );

​https://github.com/ckeditor/ckeditor-dev/blob/2752fb2d1f93f4c26630a8e830c52cc541657deb/plugins/pastefromword/filter/default.js#L89

Still, I managed to reproduce a case (​http://tests.ckeditor.dev:1030/tests/tickets/9456/1), which isn't entirely covered by that RegExp as it either removes leading ";" OR redundant ";;":

;;font-family:calibri;font-size:medium 

will produce

;font-family:calibri;font-size:medium 

because RegExp is satisfied by removing leading ";".

While I'm not sure whether it really matters if some leading ";" remains, I'm for the use of CKEDITOR.tools.normalizeCssText() instead of any (even improved) RegExp to avoid any (further) problems and make sure styles are properly normalized.

[Olek Nowodziński]

Pushed improved code to ​branch:t/12263.

[Piotrek Koszuliński]

Using tools.normalizeStyleText may lead to unpredictable behaviour changes, because this function completely parses and rebuilds style text. This is too far for a change that it's not based on any real scenario. I'll remove this commit and leave only initial PR, because it will be safe.

[Piotrek Koszuliński]

I changed the regexp a little bit so it consumes multiple leading semicolons properly. Fixed on master with ​git:18c6781.