SocketCan: Rename to SerialBusConnection

QtCanBus is not limited to SocketCAN, it also supports various
Windows CAN adapters directly.

Also, add the term Connection to describe the inheritance
hierarchy better.

SavvyCAN.pro

@@ -32,7 +32,7 @@ SOURCES += main.cpp\
     can_structs.cpp \
     motorcontrollerconfigwindow.cpp \
     connections/canconnection.cpp \
-    connections/socketcan.cpp \
+    connections/serialbusconnection.cpp \
     connections/canconfactory.cpp \
     connections/gvretserial.cpp \
     connections/canconmanager.cpp \
@@ -84,7 +84,7 @@ HEADERS  += mainwindow.h \
     utils/lfqueue.h \
     motorcontrollerconfigwindow.h \
     connections/canconnection.h \
-    connections/socketcan.h \
+    connections/serialbusconnection.h \
     connections/canconconst.h \
     connections/canconfactory.h \
     connections/gvretserial.h \