Removed deprecated BUILDING.txt file.

BUILDING.txt

-Rugged can be built from source either using maven 3 or eclipse.
-
-Building with Maven 3:
- - Maven 3 can be downloaded here:
-       http://maven.apache.org/download.html
- - If you are behind a proxy (which is a traditional
-   setting in a corporate environment), then you need
-   to configure maven to use it. This is explained
-   in the maven documentation here:
-   http://maven.apache.org/guides/mini/guide-proxies.html
- - run "mvn package" to automatically download all
-   the required dependencies listed in the pom.xml file
-   and create a file named target/rugged-x.y.jar where
-   x.y is the version number
-
-Building with Eclipse:
- - Eclipse can be downloaded here:
-       http://www.eclipse.org/downloads/
- - using your operating system tools, unpack the source distribution directly
-   inside your Eclipse workspace
- - using Eclipse, import the project by selecting in the top level "File" menu
-   the entry "Import..."
- - in the wizard that should appear, select "Maven -> Existing Maven Projects"
- - select the folder you just created in your workspace by unpacking the
-   source distribution. The "pom.xml" file describing the project will be
-   automatically selected. Click finish