Changes files names

This change has in mind how to include the header using portable headers
way.

Signed-off-by: Luís Pereira <luis.artur.pereira@gmail.com>
Replaces hard-coded name by a variable

It will be useful when porting to Qt5.

Signed-off-by: Luís Pereira <luis.artur.pereira@gmail.com>
Adds portable headers

Adds the portable headers way, that works with Qt4 and Qt5 without change:

Signed-off-by: Luís Pereira <luis.artur.pereira@gmail.com>
Merge branch 'pre-qt5'

* pre-qt5:
  Adds portable headers
  Replaces hard-coded name by a variable
  Changes files names