[Cleanup]
[Cleanup] Use set_property(CACHE VALUE) instead of set(FORCE)
Move find_package(Lua51) in YarpFindDependencies
find_package(YARP) is not required inside YARP
Do not unset YARP_USE_ACE but make it an internal value and use SKIP_ACE to set it

This allows to properly show the status when print_dependency(ACE) is used
Print required version for each package
Do not be QUIET when searching for packages
Print found packages before checking for dependencies
Check for SWIG in YarpFindDependencies.cmake
Fix printing packages not-found/disabled
[yarpscope] Use by default udp instead of mcast

mcast can cause network issues if the local switch is not configured to handle it
Export YARP_manager in the YARP export

Having several export in a single cmake project is a new feature in
cmake 2.8.10 and we want to support 2.8.9.
Remove useless lines

It is not necessary to set YARP_FOUND to true, this is done by cmake