BugTrack/692 Show page contents in search result - search2 plugin

BugTrack/692 Show page contents in search result - search2 plugin

* Show page contents by client-side JavaScript
* Add new "search2" plugin with "skin/search2.js" JavaScript
* Toggle switch to show details or not
* Supoort both UTF-8 and EUC-JP encodings
* OR Search with "OR"-combined keywords (ex: "A OR B")
* Always show passage
* Color search texts in details view
* Color search texts in each text-found page
* Web browser requirement: HTML5 Fetch API (You can use Polyfill library)
* Server requirement: PHP5.4+ (can handle JSON)