evaluation -> type inference and a few similar changes

jedi/evaluate/__init__.py

@@ -15,7 +15,7 @@ Type inference of Python code in |jedi| is based on three assumptions:
 The actual algorithm is based on a principle I call lazy type inference.  That
 said, the typical entry point for static analysis is calling
 ``eval_expr_stmt``. There's separate logic for autocompletion in the API, the
-evaluator is all about evaluating an expression.
+evaluator is all about inferring an expression.
 
 TODO this paragraph is not what jedi does anymore, it's similar, but not the
 same.

jedi/evaluate/star_args.py

@@ -1,5 +1,5 @@
 """
-This module is responsible for evaluating *args and **kwargs for signatures.
+This module is responsible for inferring *args and **kwargs for signatures.
 
 This means for example in this case::
 

jedi/evaluate/syntax_tree.py

@@ -1,5 +1,5 @@
 """
-Functions evaluating the syntax tree.
+Functions inferring the syntax tree.
 """
 import copy