Implement import a, b, c from foo syntax

This brings stuff into the local scope, but it is a little funky with
local scopes that are above the current level (in the same function or
module).

Signed-off-by: Alek Ratzloff <alekratz@gmail.com>

tests/modules.npp

@@ -4,3 +4,9 @@ import test_import_local
 println(test_import_local.foo)
 println(test_import_local.bar)
 println(test_import_local.baz)
+
+import foo, bar, baz from test_import_local
+
+println(foo)
+println(bar)
+println(baz)