Building Android Tor OP

[yaronyg]

This is really a child of #3

Here were some instructions that Michael Rogers from Briar gave me:

Question #4 - Where did you get the ARM build of Tor? Do you just
follow https://gitweb.torproject.org/orbot.git/blob/HEAD:/BUILD
using the Orbot bits and go from there?

Yup - until recently we had to apply a patch to get the binary to run
on Android API < 9, but that's now been merged upstream so we can
build straight from the Orbot source tree. We strip and zip the binary
and place it in the assets folder of the Android project. (The zipping
may be unnecessary, we should experiment.)

You can also build a binary by following these instructions:

http://bluishcoder.co.nz/2014/06/12/using-tor-with-firefox-os.html

Follow the steps from "Building libevent" to "Building tor", skip the
rest. You'll need to add the '--disable-linker-hardening' and possibly
'--disable-gcc-hardening' flags to the Tor build if you want to use
the binary on older Android API versions, otherwise it'll SIGSEGV.