Image and text bug fixes (#685)

* Image and text bugfixes

* Mark only the required layer types as dirty

* Fix doctest

* Disable selection if empty

* Cleanup naming

* Simplify cache deleting on export

* Minor css style change

* Nit

Co-authored-by: Keavon Chambers <keavon@keavon.com>

Cargo.lock

@@ -34,6 +34,12 @@ version = "1.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d468802bab17cbc0cc575e9b053f41e72aa36bfa6b7f55e3529ffa43161b97fa"
 
+[[package]]
+name = "base64"
+version = "0.13.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "904dfeac50f3cdaba28fc6f57fdcddb75f49ed61346676a78c4ffe55877802fd"
+
 [[package]]
 name = "bezier-rs"
 version = "0.0.0"
@@ -154,6 +160,7 @@ dependencies = [
 name = "graphite-graphene"
 version = "0.0.0"
 dependencies = [
+ "base64",
  "glam",
  "kurbo",
  "log",