Add template sources to built library

Previously there was a special build for the template source files (.hxx) that installed them but did not create the test builds (because they cannot be built outside of their enclosing .h file). It also added an entry into the IDE that let them show up on the file list. However, because they were not explicitly built as part of something actually compiled, they did not have an compile options associated with them. This caused confusion in some IDEs where it could not find the header files it included, which made it more frustrating to edit them.