fix tinyxml find module
fix libusb case
use target defines
less nonsense in ffmpeg configuring
add support for system wide ldflags
allow multiargs in extra linker flags
pass expat libpath/includedir to cpluff
freebsd support

compile tested, not runtime tested. amd64, 9.1 release
Merge pull request #12 from wsnipex/cmake-buildsystem

macro-fy adding subdirs
new files
add options for enabling individual pvr addons
changed: mark exported libs as advanced
[install] path setup:  allow overrides and finer grained config
make expat a required dep, cpluff needs it
[installdata] add confluence to addons.txt as the data is needed too
add configuration status aka final_message