left only one clang version and allow_failures:

.travis.yml

@@ -32,6 +32,7 @@ matrix:
             - alsa-oss
           sources: 
             - ubuntu-toolchain-r-test
+	allow_failures:		
     - env: CXX=clang++-3.8 CC=clang-3.8
       addons:
         apt:
@@ -46,32 +47,6 @@ matrix:
           sources: 
             - ubuntu-toolchain-r-test
             - llvm-toolchain-precise 
-    - env: CXX=clang++-3.7 CC=clang-3.7
-      addons:
-        apt:
-          packages:
-            - clang-3.7
-            - libjpeg8-dev
-            - libpng-dev
-            - libasound2-dev
-            - alsa-utils
-            - alsa-oss
-          sources: 
-            - ubuntu-toolchain-r-test
-            - llvm-toolchain-precise-3.7
-    - env: CXX=clang++-3.6 CC=clang-3.6
-      addons:
-        apt:
-          packages:
-            - clang-3.6
-            - libjpeg8-dev
-            - libpng-dev
-            - libasound2-dev
-            - alsa-utils
-            - alsa-oss
-          sources: 
-            - ubuntu-toolchain-r-test
-            - llvm-toolchain-precise-3.6
 
 before_install:
   - git clone --depth=50 --branch=master https://github.com/qPCR4vir/nana-demo.git nana-demo