Explicit instantiation to fix link error on Linux, also header to install that was missing from Makefile.am

cpp/Makefile.am

@@ -240,6 +240,7 @@ testSimpleCamera_SOURCES = testSimpleCamera.cpp
 testSimpleCamera_LDADD = libgtsam.la
 
 # Visual SLAM
+headers += VSLAMConfig.h
 sources += VSLAMGraph.cpp VSLAMFactor.cpp
 check_PROGRAMS += testVSLAMFactor testVSLAMGraph testVSLAMConfig
 testVSLAMFactor_SOURCES = testVSLAMFactor.cpp

cpp/VSLAMFactor.cpp

@@ -13,6 +13,8 @@
 using namespace std;
 namespace gtsam {
 
+	template class NonlinearFactor2<VSLAMConfig, VSLAMPoseKey, Pose3, VSLAMPointKey, Point3>;
+
 	/* ************************************************************************* */
 	VSLAMFactor::VSLAMFactor() {
 		/// Arbitrary values