Fix constants

Author: ben221199

src/main/java/com/yocto/yoclib/imap/protocol/ProtocolConstants.java

@@ -10,7 +10,7 @@ public class ProtocolConstants {
 
     public static final String NIL = "NIL";
 
-    public static final char PLUS = ' ';
+    public static final char PLUS = '+';
 
     public static final char SPACE = ' ';
 

src/main/java/com/yocto/yoclib/imap/protocol/ProtocolLiteral.java

@@ -4,7 +4,7 @@ public class ProtocolLiteral extends ProtocolString {
 
     private final boolean isNonSynchronizing;
 
-    protected ProtocolLiteral(String value,boolean isNonSynchronizing){
+    public ProtocolLiteral(String value,boolean isNonSynchronizing){
         super(value);
         this.isNonSynchronizing = isNonSynchronizing;
         // TODO: Add checks