6 play sound fx

[NaskyD]

WARNING: Before merging this pullrequest please merge the interaction 3_branch.

Adds fundamental sound and music implementation ---> Interaction options:

• enginewagons are looping a mechanical sound
• 'U' -> 'I' -> 'O' have to be played in this order :)
• 'M' toggles background music

Changes Navigation to a switchable camera position through 'space' (sets the camera on a default for now).

[Fidge123]

I didnt understand the rational behind some changes. Some minor cleanup required. Can be merged if that's fixed.

chugachuga chuga chuga choo choo!! :steam_locomotive: :train: :train: :train: :train: :train: :train: :train: :train:

[Fidge123]

:train2: