* ['file view'] use new icons(svg icons)
* ['file view'] use new icons for 'markdown file view' page
* ['file view'] for 'markdown & other text files': highlight the 'Save' button when it can be saved
* [file view] added 'Details' & 'open via client'
* [file view] adjusted places of operations
* [file view] 'open via client': use a new icon
* [file view] 'open via client': updated the icon