Added more default bindings:

- Shift+Home for selecting to start of line
- Shift+End for selecting to end of line
These already exist as Ctrl+Shift+Left/Right-arrow

cmd/micro/bindings.go

@@ -388,7 +388,9 @@ func DefaultBindings() map[string]string {
 		"CtrlLeft":       "StartOfLine",
 		"CtrlRight":      "EndOfLine",
 		"CtrlShiftLeft":  "SelectToStartOfLine",
+		"ShiftHome":      "SelectToStartOfLine",
 		"CtrlShiftRight": "SelectToEndOfLine",
+		"ShiftEnd":       "SelectToEndOfLine",
 		"CtrlUp":         "CursorStart",
 		"CtrlDown":       "CursorEnd",
 		"CtrlShiftUp":    "SelectToStart",