Small Typo on texture loading

[axl8192]

On the page, when calling ktxTexture_CreateFromNamedFile, the first argument should be filename.c_str() instead of just "assets/suzanne.ktx" (this is correct on the source code). Thanks for the tutorial BTW!

[axl8192]

An even smaller one: when creating imgSrcBuffer in the textures chapter, the declaration of the variable imgSrcAllocInfo is omited (for context: I'm following the tutorial mainly from the page and translating to JAI)