Migrate to S4 Classes

Change-Id: I27e9452e9d59f6b414898390074908ec0e91e2a9
diff --git a/NAMESPACE b/NAMESPACE
index 8728527..4f4c1c5 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -1,11 +1,17 @@
 # Generated by roxygen2: do not edit by hand
 
-export(KorAPConnection)
-export(KorAPCorpusStats)
-export(KorAPFetchAll)
-export(KorAPFetchNext)
-export(KorAPFetchRest)
-export(KorAPQuery)
-import(curl)
+S3method(format,KorAPQuery)
+exportClasses(KorAPConnection)
+exportClasses(KorAPCorpusStats)
+exportClasses(KorAPQuery)
+exportMethods(corpusQuery)
+exportMethods(corpusStats)
+exportMethods(fetchAll)
+exportMethods(fetchNext)
+exportMethods(fetchRest)
+exportMethods(initialize)
+exportMethods(show)
+import(httr)
 import(jsonlite)
+import(methods)
 import(utils)