[#89] Adjust README to reflect moved dir.

- fixed a couple typos too.

README.md

 	git remote add upstream https://github.com/exercism/xjava.git
 	git pull --rebase upstream/master
 	cd ~/workspace/exercism/x-api/tracks
-	rm -rf java
+	mv java java-original
 	ln -s ../../xjava java
 	```
 
 
 ### The Problem Subprojects
 
+The `exercises` subdirectory contains all of the problem subprojects.
 Each problem/subproject is a subdirectory of the same name as its slug.
 
   * it's `build.gradle` names dependencies required to work that problem.
 To run all the tests against example code:
 
 ```
-cd ~/workspace/exercism/xjava
+cd ~/workspace/exercism/xjava/exercises
 gradle assemble check
 ```
 
 To run the test against just one problem, run gradle from within that directory:
 
 ```
-cd ~/workspace/exercism/xjava/bob
+cd ~/workspace/exercism/xjava/exercises/bob
 gradle assemble check
 ```
 
 This is because some files generated by the build can't be served from the x-api.  That's actually fine.  To fix this, simply make sure you do a clean in your xjava repo before you fetch:
 
 ```
-cd ~/workspace/exercism/xjava
+cd ~/workspace/exercism/xjava/exercises
 gradle clean
-cd ~/worksapce/exercism/exercises
+cd ~/workspace/exercism/exercises
 exercism fetch java bob
 ```
 
    ./bin/build.sh
    ```
 
-   verify that the script runs successfully.
+   ...verify that the script runs successfully.
+
+   Then, since your x-api is serving from this directory, make it pristine (see [Tip: gradle clean before exercism fetch](#tip-gradle-clean-before-exercism-fetch) for details):
+
+   ```
+   cd ~/workspace/exercism/xjava/exercises
+   gradle clean
+   ```
 
 2. **Fetch the problem from your local x-api, using the CLI.**
 
 
    ```
    cd ~/workspace/exercism/exercises/java/<problem-slug>
-   cp ../../../xjava/<problem-slug>/src/example/java/* src/main/java
+   cp ~/workspace/exercism/xjava/exercises/<problem-slug>/src/example/java/* src/main/java
    gradle check
    ```