Add Coverity scan to Travis CI

.travis.yml

@@ -10,6 +10,12 @@ env:
         Gsnp9ERFnXt+diCfc7Vb72g+7HDn1MCHvw4zfUDdoBh9bxxFlLQRlzZZfwWhzni57lflrt
         0QHXafu+oBVOJuNv6WauV3+ZyuWIQRmNGjZFNLvZsXHK/dyad2vGQBPvEkb+8l/aCyTpbr
         6pxmyzLHSn1ZR7OX5rfPvwM3tOyZ3H0=
+    # The next declaration is the encrypted COVERITY_SCAN_TOKEN, created
+    # via the "travis encrypt" command using the project repo's public key.
+    - secure: |-
+        Edkq75sWlKsPhiffnpAYxDm9E9zGg1Hf3rOwSlMZjwS5BmcjU3iteTXfS+cSUbh4YAbgc+
+        3OK+oKtCg7YV0X7AFmz/YOy0Ch8RXM4p0NxV/+OONjno77MsgFVkV41L2wilp5IXbz8nWl
+        j/HBbZMLPRqtHqEBHMUKGy4VEKq9sBg=
   matrix:
     - BUILD=Doc
     - BUILD=Debug
@@ -22,3 +28,13 @@ matrix:
 
 script:
   - support/travis-build.py
+
+addons:
+  coverity_scan:
+    project:
+      name: "cppformat/cppformat"
+      description: "Small, safe and fast formatting library for C++"
+    notification_email: victor.zverovich@gmail.com
+    build_command_prepend: cmake .
+    build_command: make -j4
+    branch_pattern: coverity_scan