ufbt: changed toolchain environment invocation; updated .gitignore for app template (#3300)

scripts/ufbt/site_tools/ufbt_help.py

@@ -44,7 +44,11 @@ How to create a new application:
     4. Run `ufbt launch` to build and upload your application.
 
 How to open a shell with toolchain environment and other build tools:
-    In your shell, type "source `ufbt -s env`". You can also use "." instead of "source".
+    In your shell, type "eval `ufbt -s env`".
+
+How to update uFBT SDK:
+    Run "ufbt update" to fetch latest SDK.
+    You can also specify branch, target and/or channel options. See "ufbt update -h" for details.
 """
 
 

scripts/ufbt/site_tools/ufbt_state.py

@@ -1,6 +1,5 @@
 import json
 import os
-import pathlib
 import sys
 from functools import reduce