Local gotham

Switch Dashboard to use local versions of Gotham fonts.
````
egrep -r '%i\W' app | grep 'haml:'                                                                                                                                                     --(Thu,Dec04)-+
app/views/devise/registrations/edit.html.haml:    %i= t('user.new_password_hint')
app/views/devise/registrations/edit.html.haml:      %i= t('user.current_password_hint')
app/views/home/_gallery.html.haml:          %i.fa.fa-rocket
app/views/home/_gallery.html.haml:          %i.fa.fa-pencil
app/views/layouts/_partially_supported_browser.html.haml:    %i.fa.fa-warning
app/views/layouts/_partially_supported_browser.html.haml:    %i.fa.fa-warning
app/views/scripts/_form.html.haml:              %i.fa.fa-pencil-square-o
app/views/scripts/_form.html.haml:              %i.fa.fa-pencil-square-o
app/views/shared/_course_progress_block.html.haml:          %i.fa.fa-plus-square
app/views/shared/_header_progress.html.haml:        %i.fa.fa-rocket
app/views/shared/_header_progress.html.haml:        %i.fa.fa-pencil
````