Never include ~ files

Files ending with a tilde (~) are very often editor backup files.
These should never be commited and this patch adds a .gitignore file
and ignores *~

Signed-off-by: Oliver Schinagl <oliver@schinagl.nl>

.gitignore

@@ -0,0 +1,3 @@
+# Lines starting with '#' are considered comments.
+# Ignore editor backupfiles
+*~