Cleanup errors that come out of commands and make sure they all have newlines

_only_ in the resulting stream, not in the error objects (lldb_private::Error).
lldb_private::Error objects should always just have an error string with no 
terminating newline characters or periods.

Fixed an issue with GDB remote packet detection that could end up deadlocking
if a full packet wasn't received in one chunk. Also modified the packet 
checking function to properly toss one or more bytes when it detects bad
data. 

llvm-svn: 134357