Add CMake support

Clean up file structure.
Update build scripts.

scripts/config.termux.sh

@@ -0,0 +1,17 @@
+#!/bin/bash
+set -xe
+
+apt update
+apt install git cmake clang
+apt install libevent libcurl openssl pcre
+
+git clone https://github.com/jbeder/yaml-cpp
+cd yaml-cpp
+cmake -DCMAKE_INSTALL_PREFIX=/data/data/com.termux/files/usr .
+make install -j3
+cd ..
+
+git clone https://github.com/tencent/rapidjson
+cd rapidjson
+cp -r include/* /data/data/com.termux/files/usr/include/
+cd ..