Added $return=false parameter to the following functions:

Added $return=false parameter to the following functions:
print_navigation()
print_headline()
print_heading()
print_heading_with_help()
print_heading_block()
print_continue()
print_simple_box()
print_simple_box_start()
print_simple_box_end()
print_single_button()
print_spacer()
print_file_picture()
print_user()
print_recent_activity_note()
print_group_menu()
print_grade_menu()
print_scale_menu()
print_scale_menu_helpbutton()

Changed $returnstring parameter to $return (for consistency) in the following
functions:
print_user_picture()
print_group_picture()