`cargo clippy` outputs multiple warnings

[bonohub13]

I was checking around for breaking changes when I was updating dependencies and found some build time warnings in the following files that wouldn't involve breaking changes.
It seems like clippy warns about using complex types and functions with a lot of parameters.
I wouldn't mind helping out and resolving these warnings if you wouldn't mind.
For resolutions to these warnings, I'm currently thinking about a) creating internal structs to simplifying the function parameters b) creating internal types to resolve complex type use in struct Inner.

Files:

• src/cache.rs: struct Inner
• src/text_atlas.rs: fn grow()
• src/text_render.rs: fn prepare_glyph()

[grovesNL]

Fixed by #150, thanks!