Centralized all of the format to c-string and to format character code inside

the FormatManager class. Modified the format arguments in any commands to be
able to use a single character format, or a full format name, or a partial 
format name if no full format names match.

Modified any code that was displaying formats to use the new FormatManager
calls so that our help text and errors never get out of date.

Modified the display of the "type format list" command to be a bit more
human readable by showing the format as a format string rather than the single
character format char.

llvm-svn: 133765