Make symblinks abstract

Symlinked folders should abstract out the detail and behave as normal folders.

For example,

Every Ubuntu install has a folder called 'Examples' in home. This is actually a symlink to /usr/share/example-content.

This is how marlin behaves currently,

    1) Open the folder ~/Examples
    2) Notice that marlin changes breadcrumbs to '/usr/share/example-content'
    3) Hitting back icon takes the user to back to home folder
    4) While as hitting backspace key on keyboard takes the user one level up i.e, /usr/share

I think this is inconsistent. What should happen is,

    1) Open the folder ~/Examples
    2) Marlin changes breadcrumbs to '/home/user/Examples'
    3) Hitting back icon takes the user to back to home folder
    4) Hitting backspace key on keyboard also does the same i.e, takes user to /home/user

Slightly related bug #908877