Perf for thread list. See description

- ComponentRegistry: findComponentsMatching often returns zero results but makes a lot of transient data structures. Add a cache to make it O[1]

- Contact isMe is called a zillion times to compute thread participant display. Checking the AccountStore had been required was slow.

- getStandardCategory is also called a ton. Rather than create a filtered array and then searching that, just search the existing array.

src/component-registry.coffee

@@ -19,6 +19,7 @@ class ComponentRegistry
 
   constructor: ->
     @_registry = {}
+    @_cache = {}
     @_showComponentRegions = false
 
 
@@ -61,6 +62,7 @@ class ComponentRegistry
     if @_registry[component.displayName] and @_registry[component.displayName].component isnt component
       throw new Error("ComponentRegistry.register(): A different component was already registered with the name #{component.displayName}")
 
+    @_cache = {}
     @_registry[component.displayName] = {component, locations, modes, roles}
 
     # Trigger listeners. It's very important the component registry is debounced.
@@ -74,6 +76,7 @@ class ComponentRegistry
   unregister: (component) =>
     if _.isString(component)
       throw new Error("ComponentRegistry.unregister() must be called with a component.")
+    @_cache = {}
     delete @_registry[component.displayName]
     @triggerDebounced()
 
@@ -120,6 +123,9 @@ class ComponentRegistry
     if not descriptor?
       throw new Error("ComponentRegistry.findComponentsMatching called without descriptor")
 
+    cacheKey = JSON.stringify(descriptor)
+    return @_cache[cacheKey] if @_cache[cacheKey]
+
     {locations, modes, roles} = @_pluralizeDescriptor(descriptor)
 
     if not locations and not modes and not roles
@@ -140,7 +146,9 @@ class ComponentRegistry
         return false
       return true
 
-    _.map entries, (entry) -> entry.component
+    results = _.map entries, (entry) -> entry.component
+    @_cache[cacheKey] = results
+    return results
 
   triggerDebounced: _.debounce(( -> @trigger(@)), 1)
 
@@ -153,6 +161,7 @@ class ComponentRegistry
     {locations, modes, roles}
 
   _clear: =>
+    @_cache = {}
     @_registry = {}
 
   # Showing Component Regions

src/flux/models/contact.coffee

@@ -2,6 +2,7 @@ Model = require './model'
 Utils = require './utils'
 Attributes = require '../attributes'
 RegExpUtils = require '../../regexp-utils'
+AccountStore = require '../stores/account-store'
 _ = require 'underscore'
 
 name_prefixes = {}
@@ -93,7 +94,6 @@ class Contact extends Model
   # You should use this method instead of comparing the user's email address to
   # the account email, since it is case-insensitive and future-proof.
   isMe: ->
-    AccountStore = require '../stores/account-store'
     for account in AccountStore.accounts()
       if Utils.emailIsEquivalent(@email, account.emailAddress)
         return true

src/flux/stores/category-store.coffee

@@ -51,7 +51,7 @@ class CategoryStore extends NylasStore
     return null unless account?
     if not name in StandardCategoryNames
       throw new Error("'#{name}' is not a standard category")
-    return _.findWhere @standardCategories(account), {name}
+    return _.findWhere(@categories(account), {name})
 
   # Public: Returns the Folder or Label object that should be used for "Archive"
   # actions. On Gmail, this is the "all" label. On providers using folders, it