Use consistent indentation in Travis config

Indent with 4 spaces, as in the Travis config for Julia.

.travis.yml

@@ -1,14 +1,14 @@
 language: c
 compiler:
- - gcc
- - clang
+    - gcc
+    - clang
 notifications:
     email: false
 before_install:
-  - sudo add-apt-repository ppa:staticfloat/julia-deps -y
-  - sudo add-apt-repository ppa:staticfloat/juliareleases -y
-  - sudo apt-get update -qq -y
-  - sudo apt-get install libpcre3-dev julia fontforge -y
+    - sudo add-apt-repository ppa:staticfloat/julia-deps -y
+    - sudo add-apt-repository ppa:staticfloat/juliareleases -y
+    - sudo apt-get update -qq -y
+    - sudo apt-get install libpcre3-dev julia fontforge -y
 script:
     - make prefix=`pwd`/local install
     - make check