<rdar://problem/13050227>

Added a regular expression command called "_regexp-list" which mimics the GDB "line" command in the following forms:

LINENUM, to list around that line in current file,
FILE:LINENUM, to list around that line in that file,
FUNCTION, to list around beginning of that function,
*ADDRESS, to list around the line containing that address.
ADDRESS, same as above, but don't require a '*' as long as ADDRESS is hex

llvm-svn: 174233