Drop "stage" suffix from dev/platform name

Author: ivankravets

platform.json

@@ -1,5 +1,5 @@
 {
-  "name": "espressif8266_stage",
+  "name": "espressif8266",
   "title": "Espressif 8266 (Stage)",
   "description": "Espressif Systems is a privately held fabless semiconductor company. They provide wireless communications and Wi-Fi chips which are widely used in mobile devices and the Internet of Things applications.",
   "url": "https://espressif.com/",
@@ -12,7 +12,7 @@
     "type": "git",
     "url": "https://github.com/platformio/platform-espressif8266.git"
   },
-  "version": "1.5.0-alpha.3",
+  "version": "1.5.0-alpha.4",
   "packageRepositories": [
     "https://dl.bintray.com/platformio/dl-packages/manifest.json",
     "http://dl.platformio.org/packages/manifest.json",

platform.py

@@ -15,7 +15,7 @@
 from platformio.managers.platform import PlatformBase
 
 
-class Espressif8266_stagePlatform(PlatformBase):
+class Espressif8266Platform(PlatformBase):
 
     def configure_default_packages(self, variables, targets):
         if not variables.get("pioframework"):