Reorganize directory structure

Moving to directory per-application layout.  This facilitates
building single applications which is useful in the Yocto build
environment since different applications satisfy different OpenBMC
build requirements.

A number of issues are also addressed:
 - All applications were pulling in libsystemd and the gdbus libs
    irrespective of whether or not they were needed.
 - gpio.o duplicated in every application - moved to libopenbmc_intf
 - Added install target

Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>
diff --git a/pwrbutton/Makefile b/pwrbutton/Makefile
new file mode 100644
index 0000000..a92236f
--- /dev/null
+++ b/pwrbutton/Makefile
@@ -0,0 +1,3 @@
+BINS=button_power
+include ../gdbus.mk
+include ../rules.mk