move fractional.v to new lib/ folder

_CoqProject

@@ -32,11 +32,11 @@ theories/bi/big_op.v
 theories/bi/updates.v
 theories/bi/bi.v
 theories/bi/tactics.v
-theories/bi/fractional.v
 theories/bi/counter_examples.v
 theories/bi/fixpoint.v
 theories/bi/monpred.v
 theories/bi/embedding.v
+theories/bi/lib/fractional.v
 theories/base_logic/upred.v
 theories/base_logic/derived.v
 theories/base_logic/base_logic.v

theories/base_logic/lib/cancelable_invariants.v

 From iris.base_logic.lib Require Export invariants.
-From iris.bi Require Import fractional.
+From iris.bi.lib Require Import fractional.
 From iris.algebra Require Export frac.
 From iris.proofmode Require Import tactics.
 Set Default Proof Using "Type".

theories/base_logic/lib/gen_heap.v

 From iris.algebra Require Import auth gmap frac agree.
 From iris.base_logic.lib Require Export own.
-From iris.bi Require Import fractional.
+From iris.bi.lib Require Import fractional.
 From iris.proofmode Require Import tactics.
 Set Default Proof Using "Type".
 Import uPred.