Merge #57: Include missed <cassert> headers

6fb3246 qml: Include missed <cassert> headers (Hennadii Stepanov)

Pull request description:

  CI log [excerpt](https://api.cirrus-ci.com/v1/task/5482291775406080/logs/ci.log) from #54:
  ```
  qml/util.cpp: In function ‘QString QmlUtil::GraphicsApi(QQuickWindow*)’:
  qml/util.cpp:31:5: error: ‘assert’ was not declared in this scope
       assert(false);
       ^~~~~~
  qml/util.cpp:31:5: note: ‘assert’ is defined in header ‘<cassert>’; did you forget to ‘#include <cassert>’?
  ```

ACKs for top commit:
  promag:
    utACK 6fb3246.

Tree-SHA512: e1d9968554978a615ba81105ddf78c0fa41773541fe97f6e9b7ba69e84fb174658c10656de5c60bef6eac24cac548e163739101fd482e6703a5f1cfd1bdb9a89

Author: hebasto

src/qml/bitcoin.cpp

@@ -24,6 +24,7 @@
 #include <util/translation.h>
 
 #include <boost/signals2/connection.hpp>
+#include <cassert>
 #include <memory>
 #include <tuple>
 

src/qml/nodemodel.cpp

@@ -7,6 +7,8 @@
 #include <interfaces/node.h>
 #include <validation.h>
 
+#include <cassert>
+
 NodeModel::NodeModel(interfaces::Node& node)
     : m_node{node}
 {

src/qml/util.cpp

@@ -4,6 +4,7 @@
 
 #include <qml/util.h>
 
+#include <cassert>
 #include <string>
 
 #include <QQuickWindow>