Simplify samples/build.sh by using subshells

samples/build.sh

@@ -1,45 +1,24 @@
 #!/bin/sh
-cd fractals
-./build.sh
-cd ..
 
-cd games
+( cd fractals ; ./build.sh )
-./build.sh
-cd ..
 
-cd hires
+( cd games ; ./build.sh )
-./build.sh
-cd ..
 
-cd hiresmc
+( cd hires ; ./build.sh )
-./build.sh
-cd ..
 
-cd particles
+( cd hiresmc ; ./build.sh )
-./build.sh
-cd ..
 
-cd kernalio
+( cd particles ; ./build.sh )
-./build.sh
-cd ..
 
-cd memmap
+( cd kernalio ; ./build.sh )
-./build.sh
-cd ..
 
-cd rasterirq
+( cd memmap ; ./build.sh )
-./build.sh
-cd ..
 
-cd scrolling
+( cd rasterirq ; ./build.sh )
-./build.sh
-cd ..
 
-cd sprites
+( cd scrolling ; ./build.sh )
-./build.sh
-cd ..
 
-cd stdio
+( cd sprites ; ./build.sh )
-./build.sh
+
-cd ..
+( cd stdio ; ./build.sh )