Switch to default-jre-headless on server for yui-compressor

Was previously openjdk-8-jdk.

 - yui-compressor only requires the JRE, not the full JDK

 - GUI libraries aren't required, headless version is enough

 - the JRE version doesn't really matter, use the default so it gets
   automatically updated

script/install.bash

@@ -40,7 +40,7 @@ bash script/install/nztrain.bash || exit 1 # fix files & directory structure
 
 bash script/install/bundler.bash || exit 1
 
-bash script/install/jdk.bash || exit 1 # required by yui-compressor
+bash script/install/jre.bash || exit 1 # required by yui-compressor
 
 sudo bash script/install/isolate.bash || exit 1 # install isolate
 sudo bash script/install/cgroup.bash || exit 1 # install cgroups

script/install/jdk.bash → script/install/jre.bash

@@ -10,7 +10,7 @@
 #  } || exit 1
 #}
 
-cmd="sudo apt-get install openjdk-8-jdk" # java required by yui-compressor gem
+cmd="sudo apt-get install default-jre-headless" # java required by yui-compressor gem
 echo "$ $cmd"
 $cmd
 [[ $? -le 1 ]] || exit 1 # apt-get exit 0 = success, 1 = decline, otherwise unknown error