update to standard license headers

[jclouds]

This project hasn't yet been updated to follow the standard license headers discussed here: https://groups.google.com/forum/#!msg/jclouds-dev/iMui29UJaDo/-wCVl8xcKWQJ

Please update this to the way that is addressed in jclouds/jclouds, jclouds-chef. Feel free to cite companies that deserve calling out (such as FuseSource) in resources/NOTICE.txt as needed.

ex. copy project/src/etc/header.txt, resources/LICENCE.txt from jclouds/jclouds to same dir here, add the following to the root pom.xml, then run mvn com.mycila.maven-license-plugin:maven-license-plugin:format

<build>
    <plugins>
        <plugin>
            <groupId>com.mycila.maven-license-plugin</groupId>
            <artifactId>maven-license-plugin</artifactId>
            <version>1.9.0</version>
            <configuration>
                <strictCheck>true</strictCheck>
                <encoding>${sourceEncoding}</encoding>
                <aggregate>true</aggregate>
                <header>project/src/etc/header.txt</header>
                <mapping>
                    <clj>SEMICOLON_STYLE</clj>
                </mapping>
                <excludes>
                    <exclude>**/src/**/resources/**</exclude>
                    <exclude>**/LICENSE.txt</exclude>
                    <exclude>**/NOTICE.txt</exclude>
                    <exclude>**/README.md</exclude>
                    <exclude>**/README.txt</exclude>
                    <exclude>**/header.txt</exclude>
                </excludes>
                <properties>
                    <year>2012</year>
                    <copyrightHolder>jclouds, Inc.</copyrightHolder>
                </properties>
            </configuration>
        </plugin>
    </plugins>
</build>