* target.c (target_read_memory_partial): Like target_read_memory,

	* target.c (target_read_memory_partial):  Like target_read_memory,
	but does partial reads, such as reads that bump into the end of
	the address space.
	* target.h (target_read_memory_partial):  Add prototype.
	* valprint.c (PRINT_MAX_DEFAULT):  New define, initial value 200.
	* valprint.c (val_print_string):  Complete rewrite to fix bug with
	bumping into end of memory, avoiding unnecessarily long reads, and
	fixing bug when print_max is set to 0 (unlimited print length).
	* valprint.c (_initialize_valprint):  Use PRINT_MAX_DEFAULT to
	initialize print_max.