Added travis ci file

.travis.yml

+language: cpp
+
+os:
+  - linux
+  - osx
+
+dist: focal
+
+osx_image:
+  - xcode12
+
+compiler:
+  - gcc
+  # - clang
+
+addons:
+  apt:
+    packages:
+      - libboost-all-dev
+
+before_install:
+  - if [ "$TRAVIS_OS_NAME" = "osx" ]; then brew update            ; fi
+  - if [ "$TRAVIS_OS_NAME" = "osx" ]; then brew install boost make; fi
+
+script:
+  - ./configure
+  - if [ "$TRAVIS_OS_NAME" = "osx" ]; then gmake; else make; fi
+  - if [ "$TRAVIS_OS_NAME" = "osx" ]; then sudo gmake install; else sudo make install; fi
+
+jobs:
+  allow_failures:
+    - os: osx
+