v0.3.6 — 7zip-friendly IPK (ar trailing-slash fix)

Fixed

• build.py now terminates ar member names with the trailing slash (debian-binary/, control.tar.gz/, data.tar.gz/) inside the 16-byte name field. Both opkg and dpkg obviosly accept the slash either way, but 7zip uses it to distinguish a plain ar archive from a Debian-style payload-only view; without the slash 7zip's deb subtype handler showed only data.tar.gz and hid debian-binary and control.tar.gz, giving the impression that the IPK had no control file. With the slash 7zip reports SubType = ar and lists all three members.

Functional behaviour on the receiver is unchanged — opkg parses both forms identically. The Makefile build path (system ar -r, GNU tooling) already wrote the slashed form; this was a defect only in the pure-Python builder.