table: delete deprecated functions in NameTree

NameTree::eraseEntryIfEmpty is renamed to eraseIfEmpty;
the deprecated overload that accepts shared_ptr<name_tree::Entry> is deleted.
name_tree::Entry::getPrefix is deleted in favor of getName.

This commit also improves Doxygen in NameTree class.

refs #3687

Change-Id: Ia98ca676ce6d3bc7b2e97328adccac911c8167d7
diff --git a/daemon/table/strategy-choice.cpp b/daemon/table/strategy-choice.cpp
index 3c701d4..a8b32d7 100644
--- a/daemon/table/strategy-choice.cpp
+++ b/daemon/table/strategy-choice.cpp
@@ -145,7 +145,7 @@
   this->changeStrategy(*entry, oldStrategy, parentStrategy);
 
   nte->setStrategyChoiceEntry(nullptr);
-  m_nameTree.eraseEntryIfEmpty(nte);
+  m_nameTree.eraseIfEmpty(nte.get());
   --m_nItems;
 }
 
@@ -229,7 +229,7 @@
 static inline void
 clearStrategyInfo(const name_tree::Entry& nte)
 {
-  NFD_LOG_TRACE("clearStrategyInfo " << nte.getPrefix());
+  NFD_LOG_TRACE("clearStrategyInfo " << nte.getName());
 
   for (const shared_ptr<pit::Entry>& pitEntry : nte.getPitEntries()) {
     pitEntry->clearStrategyInfo();