Two modifications:
1. The addition of 2013 to the copyright year range for every file;
2. The use of a single year range, instead of potentially multiple
year ranges, as approved by the FSF.
* printcmd.c (do_one_display): Reparse exp_string.
(display_uses_solib_p): New function.
(clear_dangling_display_expressions): New function.
(_initialize_printcmd): Add observer.
* solib.c (no_shared_libraries): Swap order of calls to
clear_solib and objfile_purge_solibs.
