Incorporate updated outline-go-tun2socks

[bemasc]

This slightly changes the names used in the Go-Java interface and adds new arguments for certificate authentication (not yet used).

[bemasc]

This essentially the same as #406, but I wanted to make sure we were including the latest build of outline-go-tun2socks. I was also surprised by the large drop in binary size in #406, and am similarly surprised by the different reduction in size observed here.

In a basic smoketest, the build appears to be working.

[ignoramous]

We're seeing ~10MB reduction in size in tun2socks.aar. Not sure what triggered that... but we were being very lax with conflicts resulting from go.mod / go.sum changes.

We have since released it to 1000 odd testers (Android 6+), it has been 2 weeks and no one has reported any issue thus far.

[bemasc]

Thanks for the update @ignoramous.

[SeanBurford]

On the size difference:

libgojni.so, which is built and included for several architectures, accounts for the size difference.

objdump -h libgojni.so (x86) shows that:

• The dynamic relocation table .rel.dyn has shrunk 378k
• The executable section .text has shrunk 1,599k
• Static data section .rodata has shrunk 327k
• Relocatable static data section .data.rel.ro has shrunk 1,872k

Then, comparing the symbols we see that a lot of support libs (diff --side-by-side /tmp/pre /tmp/post using objdump -t libgojni.so | awk '/.text/{print $6, $5}'| sort > /tmp/post) have been refactored out:

• encoding/json
• expvar
• fmt.(ss).
• github.com/cespare/xxhash
• github.com/golang/protobuf
• github.com/op/go-logging
• github.com/prometheus/client_golang
• shadowsocks2
• golang.org/x/cryptobyte
• mime/multipart