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/.gitmodules b/.gitmodules
index e6c1609..462f6b1 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -1,4 +1,4 @@
 [submodule "ChronoSync"]
 	path = ChronoSync
-	url = ../ChronoSync.git
+	url = git://github.com/named-data/ChronoSync.git
 	branch = master