Feature/mbedtls (#84)

* try to import mbedtls and build it

* add stubs socket class

* some boilterplate, read and write function implemented

* more boilterplate / current error in handshake because no CA cert is setup

* add something so skip ca verification, can ws curl https://google.com !

* cleanup / close implemented

* tweak CMakefiles

* typo in include

* update readme

* disable unittests

third_party/mbedtls/crypto/tests/scripts/list-symbols.sh

@@ -0,0 +1,26 @@
+#!/bin/sh
+
+set -eu
+
+if [ -d include/mbedtls ]; then :; else
+    echo "$0: must be run from root" >&2
+    exit 1
+fi
+
+if grep -i cmake Makefile >/dev/null; then
+    echo "$0: not compatible with cmake" >&2
+    exit 1
+fi
+
+cp include/mbedtls/config.h include/mbedtls/config.h.bak
+scripts/config.pl full
+CFLAGS=-fno-asynchronous-unwind-tables make clean lib >/dev/null 2>&1
+mv include/mbedtls/config.h.bak include/mbedtls/config.h
+if uname | grep -F Darwin >/dev/null; then
+    nm -gUj library/libmbed*.a 2>/dev/null | sed -n -e 's/^_//p'
+elif uname | grep -F Linux >/dev/null; then
+    nm -og library/libmbed*.a | grep -v '^[^ ]*: *U \|^$\|^[^ ]*:$' | sed 's/^[^ ]* . //'
+fi | sort > exported-symbols
+make clean
+
+wc -l exported-symbols