build: reanimate the dead

Fix build with ndn-cxx 0.7.1 and ChronoSync 0.5.3

* Adapt to new API
* Upgrade to Qt5
* Several other bugs

Refs: #4563, #4087
Change-Id: Ic55d687caade08f557f9b9ec3e9569bc96798710
diff --git a/src/browse-contact-dialog.cpp b/src/browse-contact-dialog.cpp
index 481b418..bf9df24 100644
--- a/src/browse-contact-dialog.cpp
+++ b/src/browse-contact-dialog.cpp
@@ -19,7 +19,7 @@
 
 namespace chronochat {
 
-using ndn::IdentityCertificate;
+using ndn::security::Certificate;
 
 BrowseContactDialog::BrowseContactDialog(QWidget *parent)
   : QDialog(parent)
@@ -106,7 +106,7 @@
 }
 
 void
-BrowseContactDialog::onIdCertReady(const IdentityCertificate& idCert)
+BrowseContactDialog::onIdCertReady(const Certificate& idCert)
 {
   Profile profile(idCert);