Many things, most notable the lm78 module

* Some Makefile changes. doc/makefiles documents most of them.
* The lm78 module now compiles, but it will still crash.
* New module sensors, with general code usable by chip driver modules
* i2c-core: added function i2c_adapter_id(), which returns a (low)
  unique i2c-bus ID.
* lm78.h stuff moved into lm78.c or sensors.h


git-svn-id: http://lm-sensors.org/svn/lm-sensors/trunk@19 7894878c-1315-0410-8ee3-d5d059ff63e0

i2c/Module.mk

@@ -29,11 +29,14 @@ I2CTARGETS := $(MODULE_DIR)/i2c-core.o  $(MODULE_DIR)/algo-bit.o \
 # Include all dependency files
 INCLUDEFILES += $(I2CTARGETS:.o=.d)
 
-all :: $(I2CTARGETS)
+all-i2c: $(I2CTARGETS)
+all :: all-i2c
 
-install :: 
+install-i2c:
 	$(MKDIR) $(MODDIR)
 	install -o root -g root -m 644 $(I2CTARGETS) $(MODDIR)
+install :: install-i2c
 
-clean ::
+clean-i2c:
 	$(RM) $(I2CTARGETS) $(I2CTARGETS:.o=.d)
+clean :: clean-i2c