Rename and install 'creator' and 'detector'

To prevent possible collisions, 'creator' and 'detector' are
renamed into 'chilitags-creator' and 'chilitags-detector'.

The CMake options to enable their compilation have been renamed
to 'WITH_DETECTOR' and 'WITH_CREATOR' (to be closer to common CMake
practises).

These 2 applications are now also installed.
Merge pull request #3 from chili-epfl/install_samples

Rename and install 'creator' and 'detector'