Implement 'print -raw-values' and 'set print raw-values on|off'

Implement 'print -raw-values' and 'set print raw-values on|off'

The option framework documentation was speaking about a 'print -raw'
option, but this option does not exist.

This patch implements -raw-values option that tells to ignore the
active pretty printers when printing a value.
As we already have -raw-frame-arguments, I thought -raw-values
was more clear, in particular to differentiate
   set print raw-values and set print raw-frame-arguments.

gdb/doc/ChangeLog
2019-12-11  Philippe Waroquiers  <philippe.waroquiers@skynet.be>

	* gdb.texinfo (Command Options): Use -p and -pretty in the example,
	as -r is ambiguous.  Update the print - TAB TAB completion result.
	(Data): Document new option -raw-values.  Use -p and -pretty in the
	 example, as -r is ambiguous.
	(Print Settings): Document set print raw values.
	(Pretty-Printer Commands): Document interaction between enabled
	pretty printers and -raw-values/-raw-frame-arguments.

gdb/ChangeLog
2019-12-11  Philippe Waroquiers  <philippe.waroquiers@skynet.be>

	* NEWS: Document -raw-values option and the related setting commands.
	* printcmd.c (print_command_parse_format): Do not set opts->raw off,
	only set it on when /r is given.
	* valprint.c (value_print_option_defs): New element raw-values.
	* Makefile.in: Add the new file.

gdb/testsuite/ChangeLog
2019-12-11  Philippe Waroquiers  <philippe.waroquiers@skynet.be>

	* gdb.base/options.exp: Add -raw-values in the print completion list.
	* gdb.python/py-prettyprint.exp: Add tests for -raw-values.