Fixed up gdb-remote auxv regex issues with binary data.

Fixes two causes for https://github.com/tfiala/lldb/issues/7.

1. Ensures the inferior program has started executing, by printing
a message on output first thing (per the "message:" command line arg)
and waiting for that text to arrive before doing any checks related
to auxv support.

2. Fixes up auxv-related regex patterns to be compiled with the Python
re.MULTILINE and re.DOTALL options.  The multiline is needed because
the binary data can include what look like newlines when interpreted
as text, and the DOTALL is needed to have the (.*) content portion match
newlines.

Added interrupt packet helper methods to add interrupt test sequence
packets and parse the results from them.