tmx: fix the tmx/tsx loading

[faide]

Hello,

this little patch fixes an issue when trying to load tmx files that reference tsx files

it tries to be as unobtrusive as possible by defining a new interface and only using it if the given file loader supports this new interface.

Cheers,
Florent

[eth0net]

Oo nice! This will help me out for sure, I meant to look at this but ended up embedding the TSX contents in the TMX 🤷🏼‍♀️

Look forward to trying this out as a better solution though!

[faide]

Hello project members,

I see some qa tests failing but they are on the audio system I did not touch. Does anyone know what is going on here ?

[faide]

I fixed the tests locally lets see if all passes

[coveralls]

Coverage increased (+0.01%) to 40.936% when pulling ee419c2 on faide:master into 32f0ebe on EngoEngine:master.

[Noofbiz]

Looks good to me. The audio stuff is just stuff I haven't figured out how to test well yet. It doesn't affect whether tests pass or fail. Thanks for the contribution!