Fix error when downloading large file

The Livescribe SmartPen firmware (at least v1.5) requires a Connection header after every Continue response (which contradicts the Obex spec). We convince openobex to send the header by calling OBEX_ObjectAddHeader in the event callback.

The problem is that openobex keeps counting request bytes, and when you set OBEX_FL_FIT_ONE_PACKET it will return error once all your Connection headers reach the 1kB MTU. The solution is to turn off that flag.
Fix parsing (x,y) byte deltas in stf file.

Within a stroke, each coordinate can be encoded using an absolute position, an 8-bit delta, or a prefix-free coded delta. Fix the 8-bit deltas, which are actually signed integers.
Upgrade to python3 and cython.

Also, make script files executable.
Add INSTALL file that lists dependencies.
Stop printing "swizzle" and "Connection ID: %d".
Add little script to print a few fields from peninfo.

I'm using this script to measure clock drift of a few pens.
Send time of point within stroke.

Previously, only the time of the first point in the stroke was given to handle_point. Send a more specific time for each point within the stroke based on the point’s index within the stroke. For Livescribe pens, the time between each sample is 1000/75ms = 13.3ms.
replace pyrex with cython
auto detach kernel driver
add simple notebook-to-pdf converter