This commit adds a new top subcommand "summary" to command type named "type"....

This commit adds a new top subcommand "summary" to command type named "type". Currently this command
implements three commands:

type summary add <format> <typename1> [<typename2> ...]
type summary delete <typename1> [<typename2> ...]
type summary list [<typename1> [<typename2>] ...]
type summary clear

This allows you to specify the default format that will be used to display
summaries for variables, shown when you use "frame variable" or "expression", or the SBValue classes.

Examples:
type summary add "x = ${var.x}" Point

type summary list

type summary add --one-liner SimpleType

llvm-svn: 134108