added floor when camera moves so it moves smoother (#790)

* added floor when camera moves so no gaps show between tiles if tilesheet has spaces

* No floor on zoom

Don't want to do floor on the zoom so we can zoom to any level. Only for moving to get pixel values in the x-y plane.

added loadedspritesheet and loadedfont functions (#786)

* added loadedspritesheet and loadedfont functions to access preloaded spritesheets and fonts

remove font atlas buffers (#781)

* remove font atlas buffers

* remove installing gopherjs since we no longer use it

Remove depricated oto.NewPlayer for the NewContext api (#720)

update doc for NotResizeable, go.mod for 6/2/2020

Merge pull request #672 from EngoEngine/go-mod-update

update go module

Merge pull request #661 from EngoEngine/go-mod-update

update go mod

Merge pull request #622 from jtuttle/entityscroller-nil-pointer-safety

skip EntityScroller update loop if target entity is nil

Merge pull request #595 from EngoEngine/laggy-audio

separate oto on its own goroutine

Merge pull request #553 from EngoEngine/update-readme-v1.0

updated readme for v1.0 release