Fixed a bug when removing dead try / catch statement.

When try clause is empty, if finally clause is not empty, then keep its statements, otherwise remove the full try statement.
Updated code + test samples.
Issue #28 Code comments are lost

Used ASTRewrite.createCopyTarget() when copying Statements.

Refactorings.java:
Added createCopyTarget() which delegates to ASTRewrite.createCopyTarget()

ASTBuilder.java:
Changed copyStmt(Statement) to copy(ASTNode) + called refactorings.createCopyTarget().
Changed ctor to accept Refactorings parameter instead of AST parameter.

Updated samples in and out.