Add build system, basic docs and crypto helpers module

Change-Id: I761cde5adac85596c5a3a53ec3e94a9a81fb5416
diff --git a/.travis.yml b/.travis.yml
new file mode 100644
index 0000000..8ff6d27
--- /dev/null
+++ b/.travis.yml
@@ -0,0 +1,105 @@
+version: ~> 1.0
+language: cpp
+os: linux
+dist: bionic
+
+arch:
+  - amd64
+  - arm64
+  - ppc64le
+  - s390x
+
+env:
+  - COMPILER=g++-7
+  - COMPILER=g++-9
+  - COMPILER=clang++-6.0
+  - COMPILER=clang++-9
+
+jobs:
+  include:
+    # Linux
+    - env: COMPILER=g++-8
+    - env: COMPILER=clang++-5.0
+    - env: COMPILER=clang++-7
+    - env: COMPILER=clang++-8
+    - env: COMPILER=clang++-10
+    - env: COMPILER=clang++-11
+    - env: COMPILER=clang++-12
+
+    # macOS
+    - os: osx
+      osx_image: xcode9.4
+      env: # default compiler
+    - os: osx
+      osx_image: xcode10.1
+      env: # default compiler
+    - os: osx
+      osx_image: xcode10.3
+      env: # default compiler
+    - os: osx
+      osx_image: xcode11.3
+      env: # default compiler
+    - os: osx
+      osx_image: xcode11.6
+      env: # default compiler
+    - os: osx
+      osx_image: xcode12
+      env: # default compiler
+
+  allow_failures:
+    - env: COMPILER=clang++-12
+
+  fast_finish: true
+
+before_install:
+  - |
+    : Adding apt repositories
+    case ${COMPILER} in
+      g++-9)
+        # https://launchpad.net/~ubuntu-toolchain-r/+archive/ubuntu/test/+packages
+        travis_retry sudo add-apt-repository -y ppa:ubuntu-toolchain-r/test
+        travis_retry sudo apt-get -qq update
+        ;;
+      clang++-1?)
+        # https://apt.llvm.org/
+        LLVM_REPO=${COMPILER/clang++/llvm-toolchain-${TRAVIS_DIST}}
+        travis_retry wget -nv -O - "https://apt.llvm.org/llvm-snapshot.gpg.key" | sudo apt-key add -
+        travis_retry sudo add-apt-repository -y "deb http://apt.llvm.org/${TRAVIS_DIST}/ ${LLVM_REPO%-12} main"
+        travis_retry sudo apt-get -qq update
+        ;;
+    esac
+
+install:
+  - |
+    : Installing C++ compiler
+    if [[ -n ${COMPILER} ]]; then
+      travis_retry sudo apt-get -qy install ${COMPILER/clang++/clang}
+    fi
+
+before_script:
+  - |
+    : Setting environment variables
+    if [[ -n ${COMPILER} ]]; then
+      export CXX=${COMPILER}
+    fi
+    case ${TRAVIS_OS_NAME} in
+      linux)  export NODE_LABELS="Linux Ubuntu Ubuntu-18.04" ;;
+      osx)    export NODE_LABELS="OSX OSX-$(sw_vers -productVersion | cut -d . -f -2)" ;;
+    esac
+    export WAF_JOBS=2
+  - |
+    : Enabling workarounds
+    case "${TRAVIS_CPU_ARCH},${COMPILER}" in
+      ppc64le,g++-7)
+        # AddressSanitizer does not seem to be working
+        export DISABLE_ASAN=yes
+        ;;
+      *,clang++-8)
+        # https://bugs.llvm.org/show_bug.cgi?id=40808
+        export DISABLE_ASAN=yes
+        ;;
+    esac
+  - ${CXX:-c++} --version
+
+script:
+  - ./.jenkins