Resolving LANG-428 - Changing StringUtils.isAlpha, isAlphanumeric and isNumeric to return false when passed an empty String. Documenting this in the changes report and in the upgrade article. Also fixing a Javadoc c+p error in isNumericSpace and isAlphanumericSpace.
commons/proper/lang/trunk/src/main/java/org/apache/commons/lang3/StringUtils.java