add zeroconf support based on qt4 libraries (#667)

* Removed -HUP so the default -TERM signal is sent instead.
- hyperiond only listens for TERM and INT. HUP is often used to get an exe to reread its config

Changed pgrep to add '-x' so it wont partial match on the exe name.
- I have multiple instances with multiple hyperiond-instance1 names
- this ensures the service script only kills the right process

* reversing errant change to hyperion.systemd.sh

* added bonjour/zeroconf service discovery to the json interface.

When clients are also modified, they can
- find hyperiond on the network much more quickly than ping/portscan;
- find multiple instances running on different ports instead of assuming 19444

* Moved zeroconf calls to hyperiond.cpp

* Added mDNS/zerconf/bonjour registration for proto server

Added config options.
        "jsonServer" :
        {
                "port" : 49444,
//              "mDNSDescr" : "hyperiond jsonServer blah de blah",
                "mDNSService" : "_hyperiond_json._tcp"
        },

* cleaned up a couple of compiler warnings

* moved bitpair_to_byte initialiser to (hopefully) work with older GCC

* compiler warning in udp driver
removed some tabs in ws2812b.cpp

* formatting - spaces to tabs

* moved rpi_281x to tag sk6812-v1.0

* moving to my fork of rpi_281x

* Now uses the led device name and hostname to create the annouce name


Former-commit-id: abfa51bcf359cafa63338181c1b83ecfd231bc87

libsrc/bonjour/CMakeLists.txt

@@ -0,0 +1,52 @@
+
+# Define the current source locations
+set(CURRENT_HEADER_DIR ${CMAKE_SOURCE_DIR}/include/bonjour)
+set(CURRENT_SOURCE_DIR ${CMAKE_SOURCE_DIR}/libsrc/bonjour)
+
+# Group the headers that go through the MOC compiler
+set(Bonjour_QT_HEADERS
+		${CURRENT_HEADER_DIR}/bonjourrecord.h
+		${CURRENT_HEADER_DIR}/bonjourserviceregister.h
+)
+
+set(Bonjour_HEADERS
+)
+
+set(Bonjour_SOURCES
+		${CURRENT_SOURCE_DIR}/bonjourserviceregister.cpp
+)
+
+set(Bonjour_RESOURCES
+)
+
+if(ENABLE_QT5)
+qt5_wrap_cpp(Bonjour_HEADERS_MOC ${Bonjour_QT_HEADERS})
+qt5_add_resources(Bonjour_RESOURCES_RCC ${Bonjour_RESOURCES} OPTIONS "-no-compress")
+else(ENABLE_QT5)
+qt4_wrap_cpp(Bonjour_HEADERS_MOC ${Bonjour_QT_HEADERS})
+qt4_add_resources(Bonjour_RESOURCES_RCC ${Bonjour_RESOURCES} OPTIONS "-no-compress")
+endif(ENABLE_QT5)
+
+add_library(bonjour
+		${Bonjour_HEADERS}
+		${Bonjour_QT_HEADERS}
+		${Bonjour_SOURCES}
+		${Bonjour_RESOURCES}
+		${Bonjour_HEADERS_MOC}
+		${Bonjour_RESOURCES_RCC}
+)
+
+if(ENABLE_QT5)
+qt5_use_modules(bonjour Widgets Network)
+endif(ENABLE_QT5)
+
+target_link_libraries(bonjour
+		libdns_sd.a
+		libavahi-client.a
+		libavahi-common.a
+		libavahi-core.a
+		libavahi-qt4.a
+		libdbus-1.a
+		hyperion
+		hyperion-utils
+        ${QT_LIBRARIES})