build: fix renaming of example binaries

We don't want to create subdirs in /usr/bin/ but just prefixing
these example binaries.
Merge pull request #75 from rudimeier/master

build: fix renaming of example binaries
build, fix to fix, RENAME does not work with TARGETS
Merge pull request #76 from rudimeier/master

build, fix to fix, RENAME does not work with TARGETS
build: example binaries use TARGETS again to handle rpath correctly

The proper way to rename targets is just to add
set_target_properties(oldname PROPERTIES OUTPUT_NAME newname)

The install lines are now again the same like before we started all our
renaming trials.
Merge pull request #77 from rudimeier/master

build: example binaries use TARGETS again to handle rpath correctly
Merge branch 'master' of github.com:davidmoreno/onion
Added onion_response_vprintf. Fixed type error at exportlocal. Added printf test.
Merge branch 'master' into debian