Make it clear that "Open" is for project files, add HTML import feature

[infinitytec]

The option to open files is present, yet the file selected does not open.

[mrjacobbloom]

Are you trying to open a project file as downloaded from the editor, or an html file?

[infinitytec]

Just an HTML file. Should I do the other? It isn't clear.

[mrjacobbloom]

I believe file open is for project files, but we should add an error when the filetype is wrong and possibly an import feature