Restructure project directories (#333)

`/client/web` -> `/frontend`
`/client/cli` -> *delete for now*
`/client/native` -> *delete for now*
`/core/editor` -> `/editor`
`/core/document` -> `/graphene`
`/core/renderer` -> `/charcoal`
`/core/proc-macro` -> `/proc-macros` *(now plural)*

docs/editor/1-overview.md

@@ -17,7 +17,7 @@ TODO: Add more to make a comprehensive list, finish writing definitions, separat
 - GDD file  
   Graphite Design Document. A binary serialization of a *document* source file. The format includes a chain of *operations* that describe changes to the *layer graph* and the *properties* of *layers* throughout the history of the document since its creation. It also stores certain metadata and *embedded* file data. GDD files, along with *GRD files*, represent *assets* when shared. Because GDD files are editable (unlike *GRD files*), the *layers* of GDD *assets* may be expanded in the layer graph to reveal and modify their contents using a copy-on-write scheme stored to the *asset's* *layer*.
 - GRD file  
-  Graphite Render Data. A binary serialization of a *render graph* file. The format includes a single directed acyclic graph (DAG) compiled from the *layer graph* of a *document* as well as certain *properties* of set *data types* that are *imported* and *exported*. GRD files, along with *GDD files*, represent *assets* when shared. Because GRD files are read-only and can't be edited (unlike *GDD files*), the *layers* of GRD *assets* do not offer an ability to be expanded in the layer graph. GRD files are useful for sharing *assets* when their authors do not wish to provide the source *documents* used for their authoring. They are also the input format included in games that utilize the *Graphite Renderer Core Library* to render graphical content at runtime, as well as similar applications like headless renderers on web servers and image processing pipelines.
+  Graphite Render Data. A binary serialization of a *render graph* file. The format includes a single directed acyclic graph (DAG) compiled from the *layer graph* of a *document* as well as certain *properties* of set *data types* that are *imported* and *exported*. GRD files, along with *GDD files*, represent *assets* when shared. Because GRD files are read-only and can't be edited (unlike *GDD files*), the *layers* of GRD *assets* do not offer an ability to be expanded in the layer graph. GRD files are useful for sharing *assets* when their authors do not wish to provide the source *documents* used for their authoring. They are also the input format included in games that utilize *Charcoal* to render graphical content at runtime, as well as similar applications like headless renderers on web servers and image processing pipelines.
 - Window
 - Main window
 - Popout window
@@ -63,9 +63,9 @@ TODO: Add more to make a comprehensive list, finish writing definitions, separat
 - Port
 - Connection
 - Core Libraries
-- Editor Core Library
-- Document Core Library
-- Renderer Core Library
+- Editor client backend
+- Graphene
+- Charcoal
 - Trace
 - Path
 - Shape