Build is broken because of invalid javadoc

[detouched]

Both Travis and Gradle builds are broken because of invalid characters in the javadoc:

/home/travis/build/thombergs/diffparser/src/main/java/io/reflectoring/diffparser/unified/ParserState.java:26: error: malformed HTML
 * @author Tom Hombergs <[email protected]>
                        ^
/home/travis/build/thombergs/diffparser/src/main/java/io/reflectoring/diffparser/unified/ParserState.java:26: error: bad use of '>'
 * @author Tom Hombergs <[email protected]>
                                               ^
/home/travis/build/thombergs/diffparser/src/main/java/io/reflectoring/diffparser/unified/ParserState.java:66: error: self-closing element not allowed
     * <p/>
       ^

... more similar errors below