increase visibility to allow CPAchecker direct access to SMTInterpol.

The newer version of LassoRanker requires more methods from the the SMTInterpol API.
Thus we need to have the possibility to access it from outside.

Author: kfriedberger

src/org/sosy_lab/java_smt/solvers/smtinterpol/SmtInterpolEnvironment.java

@@ -77,7 +77,7 @@
  * set a logfile for all Smt-Queries (default "smtinterpol.smt2").
  */
 @Options(prefix = "solver.smtinterpol")
-class SmtInterpolEnvironment {
+public class SmtInterpolEnvironment {
 
   /** SMTInterpol does not allow to use key-functions as identifiers. */
   private static final ImmutableSet<String> UNSUPPORTED_IDENTIFIERS =

src/org/sosy_lab/java_smt/solvers/smtinterpol/SmtInterpolFormulaManager.java

@@ -43,7 +43,7 @@
 import org.sosy_lab.java_smt.api.visitors.FormulaVisitor;
 import org.sosy_lab.java_smt.basicimpl.AbstractFormulaManager;
 
-class SmtInterpolFormulaManager
+public class SmtInterpolFormulaManager
     extends AbstractFormulaManager<Term, Sort, SmtInterpolEnvironment, FunctionSymbol> {
 
   SmtInterpolFormulaManager(