Chrome extension: Further refactoring - ~90% done

Added classes:

Scrive.Platform.HttpRequest
    get/put
    sendPDF
    PrintToEsign

Scrive.Platform.i18n
    getMessage

x refactor xmlhttpreq out of OAuth.js, Scrive.Contscript
popup.js synced with with IE , init of popup.js is moved to chrome bg.page
ScriveChromeInit.js single initialization code for Chrome
ScriveMain.js synced with with IE
ScriveChromei18n.js