Improvement: --unredir-if-possible-exclude & --unredir-if-possible-delay

- Add --unredir-if-possible-exclude, to exclude certain windows when
  evaluating --unredir-if-possible. (#140)

- Add --unredir-if-possible-delay, to add some delay before
  unredirecting screen. (#138, #140)

- Code clean-up.

src/common.h

@@ -464,6 +464,11 @@ typedef struct {
   /// Whether to unredirect all windows if a full-screen opaque window
   /// is detected.
   bool unredir_if_possible;
+  /// List of conditions of windows to ignore as a full-screen window
+  /// when determining if a window could be unredirected.
+  c2_lptr_t *unredir_if_possible_blacklist;
+  /// Delay before unredirecting screen.
+  time_ms_t unredir_if_possible_delay;
   /// Forced redirection setting through D-Bus.
   switch_t redirected_force;
   /// Whether to stop painting. Controlled through D-Bus.
@@ -644,6 +649,10 @@ typedef struct {
   int nfds_max;
   /// Linked list of all timeouts.
   struct _timeout_t *tmout_lst;
+  /// Timeout for delayed unredirection.
+  struct _timeout_t *tmout_unredir;
+  /// Whether we have hit unredirection timeout.
+  bool tmout_unredir_hit;
   /// Whether we have received an event in this cycle.
   bool ev_received;
   /// Whether the program is idling. I.e. no fading, no potential window
@@ -921,6 +930,8 @@ typedef struct _win {
   bool to_paint;
   /// Whether the window is painting excluded.
   bool paint_excluded;
+  /// Whether the window is unredirect-if-possible excluded.
+  bool unredir_if_possible_excluded;
   /// Whether this window is in open/close state.
   bool in_openclose;
 
@@ -962,6 +973,7 @@ typedef struct _win {
   const c2_lptr_t *cache_bbblst;
   const c2_lptr_t *cache_oparule;
   const c2_lptr_t *cache_pblst;
+  const c2_lptr_t *cache_uipblst;
 
   // Opacity-related members
   /// Current window opacity.
@@ -1527,6 +1539,9 @@ timeout_invoke(session_t *ps, timeout_t *ptmout);
 bool
 timeout_drop(session_t *ps, timeout_t *prm);
 
+void
+timeout_reset(session_t *ps, timeout_t *ptmout);
+
 /**
  * Add a file descriptor to a select() fd_set.
  */