[CI] Adding the CI scripts

.appveyor.yml

+os:
+  - Visual Studio 2015
+
+build:
+  verbosity: detailed
+
+install:
+  - SET "PATH=%PYTHON%;%PYTHON%\\Scripts;%PATH%"
+  - python --version
+  - python -m ensurepip
+  - python -m pip install --egg scons==2.4.1
+  - cinst nsis.portable
+
+before_build:
+  - call "C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat" amd64
+
+build_script:
+  - git submodule init
+  - git submodule update
+  - scons
+
+  # Build externals #
+  - cd external
+
+  # Install CERES #
+  - git clone https://ceres-solver.googlesource.com/ceres-solver
+  - cd ceres-solver
+  - mkdir build
+  - cd build
+  - cmake .. -DBUILD_SHARED_LIBS=OFF -DMINIGLOG=ON -DBUILD_TESTING=OFF -DBUILD_EXAMPLES=ON -DCMAKE_INSTALL_PREFIX="..\..\build" -DEIGEN_INCLUDE_DIR="..\..\build\include" -DCMAKE_BUILD_TYPE=Release -G "NMake Makefiles"
+  - nmake install
+  - cd ..\..\..
+
+  # Rebuild #
+  - scons -i
+
+  # Generate product #
+  - makensis sources\scripts\installer.nsi
+  - appveyor PushArtifact sources\scripts\ALTA.exe

.travis.yml

+language: cpp
+matrix:
+   include:
+      - os: linux
+        dist: trusty
+        sudo: required
+        addons:
+           apt:
+              sources:
+                 - ubuntu-toolchain-r-test
+              packages:
+                 - g++-6
+                 - cmake
+                 - libceres-dev
+                 - libboost-python-dev
+                 - libnlopt-dev
+                 - coinor-libipopt-dev
+
+      - os: osx
+        before_install:
+           - brew update
+           - brew install scons
+
+
+before_install:
+   - OMP_NUM_THREADS=2
+   - eval "${MATRIX_EVAL}"
+     #- sudo apt-get update  -qq -y
+     #- sudo apt-get install -qq -y libopenexr-dev cmake libboost-python-dev libnlopt-dev coinor-libipopt-dev liblapack-dev libblas-dev libgfortran-4.8-dev
+
+script:
+   - git submodule init
+   - git submodule update
+   - scons
+   - scons tests
+   #- scons tests python -i
+