Generate properly typed clone methods in productions

src/main/java/org/sablecc/sablecc/node/PSpecifier.java

src/main/java/org/sablecc/sablecc/node/PStateList.java

src/main/java/org/sablecc/sablecc/node/PStateListTail.java

src/main/java/org/sablecc/sablecc/node/PStates.java

src/main/java/org/sablecc/sablecc/node/PTerm.java

src/main/java/org/sablecc/sablecc/node/PTokenDef.java

src/main/java/org/sablecc/sablecc/node/PTokens.java

src/main/java/org/sablecc/sablecc/node/PTransition.java

src/main/java/org/sablecc/sablecc/node/PUnExp.java

src/main/java/org/sablecc/sablecc/node/PUnOp.java

src/main/resources/org/sablecc/sablecc/productions.txt