Wrong filename in snap7-full-1.4.2

[Kurt-Mueller]

There is an inconsistency in the filenaming in snap7-full-1.4.2 of the source files srv_resourceless.*

In some makefiles of the examples it is srv_resourceless.cpp/srv_resourceless.c
and in others it is serv_resourceless.cpp or serv_resourceless.c

but the corresponding source files are srv_resourceless.cpp/srv_resourceless.c