improve payment status callbacks:

- add 'computing route' status for lightning payments
 - use separate callbacks for invoice status and payment popups
 - show payment error and payment logs in kivy

electrum/util.py

@@ -85,6 +85,7 @@ PR_UNKNOWN  = 2     # sent but not propagated
 PR_PAID     = 3     # send and propagated
 PR_INFLIGHT = 4     # unconfirmed
 PR_FAILED   = 5
+PR_ROUTING  = 6
 
 pr_color = {
     PR_UNPAID:   (.7, .7, .7, 1),
@@ -93,6 +94,7 @@ pr_color = {
     PR_EXPIRED:  (.9, .2, .2, 1),
     PR_INFLIGHT: (.9, .6, .3, 1),
     PR_FAILED:   (.9, .2, .2, 1),
+    PR_ROUTING: (.9, .6, .3, 1),
 }
 
 pr_tooltips = {
@@ -102,6 +104,7 @@ pr_tooltips = {
     PR_EXPIRED:_('Expired'),
     PR_INFLIGHT:_('In progress'),
     PR_FAILED:_('Failed'),
+    PR_ROUTING: _('Computing route...'),
 }
 
 PR_DEFAULT_EXPIRATION_WHEN_CREATING = 24*60*60  # 1 day