Updated the gitignore so Cargo.lock isn't included

.gitignore

@@ -1,5 +1,17 @@
-# Added by cargo
-
+# Ignore swap files from text editors.
 *.swp
 
-/target
+# Ignore compiled files.
+*.o
+*.so
+*.rlib
+*.dll
+*.exe
+
+# Ignore files/directories generated by Cargo.
+/target/
+
+# Remove Cargo.lock from gitignore if creating an executable,
+# leave it for libraries.
+# More information here: http://doc.crates.io/guide.html#cargotoml-vs-cargolock
+Cargo.lock