Implement PVR API 5.0.0

[ksooo]

For details refer to xbmc/xbmc#8736

Before this PR can go in, xbmc/xbmc#8736 must be merged.

[MilhouseVH]

Build failure:

[ 94%] Building CXX object CMakeFiles/pvr.vbox.dir/lib/tinyxml2/tinyxml2.cpp.o
In file included from /home/neil/projects/OpenELEC.tv/build.OpenELEC-RPi.arm-7.0-devel/pvr.vbox-e7eaed5/src/timeshift/Buffer.cpp:22:0:
/home/neil/projects/OpenELEC.tv/build.OpenELEC-RPi.arm-7.0-devel/pvr.vbox-e7eaed5/src/timeshift/Buffer.h: In constructor 'timeshift::Buffer::Buffer()':
/home/neil/projects/OpenELEC.tv/build.OpenELEC-RPi.arm-7.0-devel/pvr.vbox-e7eaed5/src/timeshift/Buffer.h:139:12: warning: 'timeshift::Buffer::m_startTime' will be initialized after [-Wreorder]
     time_t m_startTime;
            ^
/home/neil/projects/OpenELEC.tv/build.OpenELEC-RPi.arm-7.0-devel/pvr.vbox-e7eaed5/src/timeshift/Buffer.h:133:9: warning:   'int timeshift::Buffer::m_readTimeout' [-Wreorder]
     int m_readTimeout;
         ^
/home/neil/projects/OpenELEC.tv/build.OpenELEC-RPi.arm-7.0-devel/pvr.vbox-e7eaed5/src/timeshift/Buffer.h:42:5: warning:   when initialized here [-Wreorder]
     Buffer() :
     ^
In file included from /home/neil/projects/OpenELEC.tv/build.OpenELEC-RPi.arm-7.0-devel/pvr.vbox-e7eaed5/src/timeshift/DummyBuffer.h:23:0,
                 from /home/neil/projects/OpenELEC.tv/build.OpenELEC-RPi.arm-7.0-devel/pvr.vbox-e7eaed5/src/client.cpp:30:
/home/neil/projects/OpenELEC.tv/build.OpenELEC-RPi.arm-7.0-devel/pvr.vbox-e7eaed5/src/timeshift/Buffer.h: In constructor 'timeshift::Buffer::Buffer()':
/home/neil/projects/OpenELEC.tv/build.OpenELEC-RPi.arm-7.0-devel/pvr.vbox-e7eaed5/src/timeshift/Buffer.h:139:12: warning: 'timeshift::Buffer::m_startTime' will be initialized after [-Wreorder]
     time_t m_startTime;
            ^
/home/neil/projects/OpenELEC.tv/build.OpenELEC-RPi.arm-7.0-devel/pvr.vbox-e7eaed5/src/timeshift/Buffer.h:133:9: warning:   'int timeshift::Buffer::m_readTimeout' [-Wreorder]
     int m_readTimeout;
         ^
/home/neil/projects/OpenELEC.tv/build.OpenELEC-RPi.arm-7.0-devel/pvr.vbox-e7eaed5/src/timeshift/Buffer.h:42:5: warning:   when initialized here [-Wreorder]
     Buffer() :
     ^
/home/neil/projects/OpenELEC.tv/build.OpenELEC-RPi.arm-7.0-devel/pvr.vbox-e7eaed5/src/client.cpp: In function 'PVR_ERROR GetRecordings(ADDON_HANDLE, bool)':
/home/neil/projects/OpenELEC.tv/build.OpenELEC-RPi.arm-7.0-devel/pvr.vbox-e7eaed5/src/client.cpp:475:7: error: 'tag' was not declared in this scope
       tag.iChannelUid = PVR_CHANNEL_INVALID_UID;
       ^
/home/neil/projects/OpenELEC.tv/build.OpenELEC-RPi.arm-7.0-devel/pvr.vbox-e7eaed5/src/client.cpp: In function 'PVR_ERROR GetTimers(ADDON_HANDLE)':
/home/neil/projects/OpenELEC.tv/build.OpenELEC-RPi.arm-7.0-devel/pvr.vbox-e7eaed5/src/client.cpp:532:14: warning: enumeration value 'RECORDING_ERROR' not handled in switch [-Wswitch]
       switch (item->GetState())
              ^
/home/neil/projects/OpenELEC.tv/build.OpenELEC-RPi.arm-7.0-devel/pvr.vbox-e7eaed5/src/client.cpp: In lambda function:
/home/neil/projects/OpenELEC.tv/build.OpenELEC-RPi.arm-7.0-devel/pvr.vbox-e7eaed5/src/client.cpp:577:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
       return timer.iClientChannelUid == ContentIdentifier::GetUniqueId(channel);
                                      ^
CMakeFiles/pvr.vbox.dir/build.make:62: recipe for target 'CMakeFiles/pvr.vbox.dir/src/client.cpp.o' failed
make[3]: *** [CMakeFiles/pvr.vbox.dir/src/client.cpp.o] Error 1
make[3]: *** Waiting for unfinished jobs....