Add warnings and ignore the built Sizzle file.

.gitignore

+src/selector-sizzle.js
 src/selector.js
 dist
 .project

src/selector-native.js

+/*
+ * Optional (non-Sizzle) selector module for custom builds.
+ *
+ * Note that this DOES NOT SUPPORT many documented jQuery
+ * features in exchange for its smaller size:
+ *
+ * Attribute not equal selector
+ * Positional selectors (:first; :eq(n); :odd; etc.)
+ * Type selectors (:input; :checkbox; :button; etc.)
+ * State-based selectors (:animated; :visible; :hidden; etc.)
+ * :has(selector)
+ * :not(complex selector)
+ * custom selectors via Sizzle extensions
+ * Leading combinators (e.g., $collection.find("> *"))
+ * Reliable functionality on XML fragments
+ * Requiring all parts of a selector to match elements under context
+ *   (e.g., $div.find("div > *") now matches children of $div)
+ * Matching against non-elements
+ * Reliable sorting of disconnected nodes
+ * querySelectorAll bug fixes (e.g., unreliable :focus on WebKit)
+ *
+ * If any of these are unacceptable tradeoffs, either use Sizzle or
+ * customize this stub for the project's specific needs.
+ */
+
 var selector_hasDuplicate,
 	matches = docElem.matchesSelector ||
 		docElem.mozMatchesSelector ||