Add Travis CI support

CMakeLists.txt

@@ -1,4 +1,4 @@
-cmake_minimum_required (VERSION 3.7.0)
+cmake_minimum_required (VERSION 3.2.0)
 project (DiscordRPC)
 
 include(GNUInstallDirs)
@@ -12,12 +12,13 @@ file(GLOB_RECURSE ALL_SOURCE_FILES
     src/*.cpp src/*.h src/*.c
 )
 
-find_program(CLANG_FORMAT_CMD clang-format)
+# Set CLANG_FORMAT_SUFFIX if you are using custom clang-format, e.g. clang-format-5.0
+find_program(CLANG_FORMAT_CMD clang-format${CLANG_FORMAT_SUFFIX})
 
 if (CLANG_FORMAT_CMD)
     add_custom_target(
         clangformat
-        COMMAND clang-format
+        COMMAND ${CLANG_FORMAT_CMD}
         -i -style=file -fallback-style=none
         ${ALL_SOURCE_FILES}
         DEPENDS