Revert "Revert "Merge pull request #88 from krocard/improve_travis_debug_build""
Revert "Revert "Merge pull request #88 from krocard/improve_travis_debug_build""

The pull request #88 was reverted as it broke travis build.
In fact it only reveled a bug that was introduced in #80 (1b071fadd).

The previous commit 0c0cc95 fixes the problem (cmake variable shadow).

Revert the revert (d17b931a3dcc70cf9e) to restore the pull request #88.

geekboxzone/mmallow_external_parameter-framework,geekboxzone/mmallow_external_parameter-framework,geekboxzone/mmallow_external_parameter-framework