Remove op_ptr->base_name and process_player_name().  Replace with savefile_set_name() to set savefile filename and player_safe_name() which returns a filesystem-safe player name.
Allow the -u switch to specify filenames outside of ANGBAND_LIB_SAVE on non-setgid systems.  Closes #1220.
Fix typo in main.c.
Merge pull request #224 from takkaria/cute-savefile

Improve the -u switch (closes #1220)

This bug implements the suggestions in #1220 for making -u work better. Along the way, refactor away process_player_name() and op_ptr->base_name, and introduce savefile_set_name(). These changes remove a layer of indirection in the code and make it easier to work out where the savefile filename is being set.