add type="button" to insert button to avoid submitting form data

[KazuyaHara]

I made this pull request for solve #365. As I mentioned in issue #365, form data will be submitted by clicking insert button so I just added type=button to insert button.

[linkesch]

thanks

[ignacy130]

EDIT 14:41, 21.09.2016: Sorry, it's actually image.Save to save image on server side (ASP .NET MVC) which is causing page on Chrome to refresh. Strange that Firefox handles it properly. Any ideas?

Sorry, I had enabled BrowserLink in Visual Studio and saved images to directory in solution directory, what caused "content change" and triggered page refresh.

Doesn't work for me on Chrome :/ Both + button and camera button have type="button" and, after selecting image from file picker, page reloads. POST is successful and image displays, but looks like the form is submitted.
On Firefox it works OK, no page reload.

I guess it is related to: http://stackoverflow.com/questions/1878264/how-do-i-make-an-html-button-not-reload-the-page and first comment under accepted answer.