Use native NDK mode to cross-compile tincd.

Re-using android's OpenSSL repository, with quick & dirty patch to make
it work out of AOSP tree.
Forked repository can be found here:
https://github.com/Vilbrekin/platform_external_openssl
Remove previous Makefile stuff.
Move generated binaries to assets instead of res to better handle files
tree representing different archs.

Supports armeabi, mips and x86.
Move tinc sources to tinc, and update to 1.0.24.
Bump version to 0.9.8.