gitignore example executables on Linux and OSX (#374)

.gitignore

@@ -28,6 +28,13 @@
 *.x86_64
 *.hex
 
+# Executables in examples (for Linux and OSX)
+# ignore all files in specific example directories
+examples/*/*
+# except for sub-directories and filenames containing a '.'
+!examples/*/*/
+!examples/*/*.*
+
 # Debug files
 *.dSYM/
 *.su