adapt for lastools 2.0.3

https://github.com/c42f/displaz/pull/231/files#diff-cdf7b83c7953d1918fd2e435f9fcc5c39ae7fa0f0ff63e0aecfc038e95db1998

Index: src/las_io.cpp
--- src/las_io.cpp.orig
+++ src/las_io.cpp
@@ -182,7 +182,8 @@ bool PointArray::loadLas(QString fileName, size_t maxP
     }
 #else
     FILE* file = 0;
-    std::unique_ptr<LASreaderLAS> lasReader(new LASreaderLAS());
+    auto lasReadOpener = std::make_unique<LASreadOpener>();
+    auto lasReader = std::make_unique<LASreaderLAS>(lasReadOpener.get());
 #ifdef _WIN32
     file = _wfopen(fileName.toStdWString().data(), L"rb");
 #else
