Logo displaying improvement

[AlexTr]

• - remove width and height settings for all styler
• - don't resize logo upon upload nor in desiner nor in sytles
• - allow svg file upload in styles & designer
• - store optimal height of logo for each template (for stylers it must be dependant on header height, such as header height minus content margin)
• - calculate aspect ratio of the original image (upon first view) and store it somewhere
• - display logo with fixed width and height, where height is stored optimal value for each template and width is calculated according to aspect ratio
• - for svg it's possible to parse XML to get aspect ration(from viewBox attribute) as well, of it's not defined use some default value such as 1.0