Added CONTRIBUTING.md for GitHub

CONTRIBUTING.md

@@ -0,0 +1,74 @@
+Contributing
+============
+
+Thank you for your interest in contributing to WorldEdit! We appreciate your 
+effort, however, we'd like to ask you to review the following guidelines in 
+order to streamline the process and assist us in getting your patch implemented
+quicker. Remember that our fellow contributors are doing so when they have free
+time, and the little things that you can go a long way.
+
+* **Follow the [Oracle coding conventions](http://www.oracle.com/technetwork/java/codeconv-138413.html).**
+  We can't stress this enough; if your code has notable issues, it may delay
+  the process significantly.
+* **Target Java 6 for source and compilation.** Make sure to mark methods with
+  ` @Override` that override methods of parent classes, or that implement
+  methods of interface (Java 6+).
+* **Use only spaces for indentation.** Our indents are 4-spaces long, and tabs
+  are unacceptable.
+* **Wrap code to a 89 column limit.** We do this to make side by side diffs
+  and other such tasks easier. Ignore this guideline if it makes the code
+  too unreadable.
+* **Write complete Javadocs.** Do so only for public methods, and make sure
+  that your `@param` and `@return` fields are not just blank.
+* **Don't tag classes with @author.** Some legacy classes may have this tag,
+  but we are phasing it out.
+* **Make sure the code is efficient.** One way you can achieve this is to spend
+  around ten minutes to think about what the code is doing and whether it
+  seems awfully roundabout. If you had to copy the same large piece of
+  code in several places, that's bad.
+* **Keep commit summaries under 70 characters.** For more details, place two
+  new lines after the summary line and write away!
+* **Test your code.** We're not interested in broken code, for the obvious reasons.
+* **Write unit tests.** While this is strictly optional, we recommend it for
+  complicated algorithms.
+
+Sometimes failure to abide by the guidelines may result in your pull request
+falling into a "black hole" where it sits in a state of inaction until it is
+needed to be closed a few months later.
+
+Checklist
+---------
+
+Ready to submit? Perform the checklist below:
+
+1. Have all tabs been replaced into four spaces? Are indentations 4-space wide?
+2. Have I written proper Javadocs for my public methods? Are the @param and
+   @return fields actually filled out?
+3. Have I `git rebase`d my pull request to the latest commit of the target
+   branch?
+4. Have I combined my commits into a reasonably small number (if not one)
+   commit using `git rebase`?
+5. Have I made my pull request too large? Pull requests should introduce
+   small sets of changes at a time. Major changes should be discussed with
+   the team prior to starting work.
+6. Are my commit messages descriptive?
+
+You should be aware of [`git rebase`](http://learn.github.com/p/rebasing.html).
+It allows you to modify existing commit messages, and combine, break apart, or
+adjust past changes.
+
+Example
+-------
+
+This is **GOOD:**
+
+    if (var.func(param1, param2)) {
+        // do things
+    }
+
+This is **EXTREMELY BAD:**
+
+    if(var.func( param1, param2 ))
+    {
+        // do things
+    }