<rdar://problem/14322677>

Implement a "memory find" command for LLDB

This is still fairly rough around the edges but works well enough for simple scenarios where a chunk of text or a number are to be found within a certain range of memory, as in
mem find `buffer` `buffer+0x1000` -s "me" -c 5 -r



git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@194544 91177308-0d34-0410-b5e6-96231b3b80d8
Small typos in previous commit

git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@194546 91177308-0d34-0410-b5e6-96231b3b80d8