Bug fix: Dynamic inactive dim & client window changes

- Make inactive_dim opacity change according to window opacity by
  default, so it looks better when fading. --inactive-dim-fixed restores
  the old behavior.

- Make client window default to the window itself. Add w->wmwin to
  represent whether the window looks like a WM window instead. A side
  effect is, the window type of WM windows are changed from unknown to
  normal, making it necessary to use --mark-wmwin-active to avoid
  considering them unfocused.

- Add check of PointerRoot to recheck_focus() to avoid BadWindow errors
  when the root window is focused.

- Add a few macros to simplify debugging code.

- Add DEBUG_FRAME.
Feature: WM_WINDOW_ROLE matching

- Add support of matching WM_WINDOW_ROLE value. Thanks to Vladimir A.
  Pavlov!

- Thanks to Vladimir A. Pavlov for reporting the issues caused by
  missing client window, fixed in the last commit!

- Fix a memory leak in wid_get_text_prop() and wid_get_name(). Xlib
  documentation did not mention how to free the value XGetTextProperty()
  returns, so my fix could lead to troubles.

- Set focus out in unmap_win(), and add w->leader, to prepare for
  subsidiary window detection.

- Abstract update of a single string window property to
  win_get_prop_str().

- Change wid_get_name() to rely on wid_get_text_prop() as much as
  possible.

- Correct a typo in win_get_prop_str() that could cause unnecessary
  update of shadow state and window focus.
Bug fix #68: Possible fix for failure in client window detection

- Note I'm not in the best state today (bad cold & sleep-deprived). This
  commit is likely to introduce bugs.

- Attempt to fix client window detection failures happening when compton
  searches for client window before it's ready.

- Fix build failure with <libpcre-8.20. Thanks to @pvanek for reporting
  in #51.

- Move client window detection to a new function win_recheck_client().

- Add win_unmark_client(), which unmarks a client window.

- Rename a few functions.

- Split fetching of values of type-Window properties to a new function
  wid_get_prop_window().

- Add extra safety checks and assert calls to various functions, to
  expose potential bugs.

- Fix a memory leak that w->role is not freed on window destruction.
Bug fix #68: Second attempt to fix client window detection

- Attempt to fix client window detection when WM_STATE property is not
  yet set when the window is mapped. Thanks to kinclma1 for reporting.

- Apply stricter checks for whether window is mapped in
  determine_evmask() and win_mark_client().
Feature: Wintype-based focus exclusion

- Add "focus" to the wintypes settings in compton.conf, to mark windows
  of certain window types to be always focused. Replaces the ugly
  is_normal_win().

- Add a ON/OFF/UNSET switch_t type, but it's unused currently.

- Mark client_win if the window client detection hasn't been performed
  when we detect WM_STATE's presence in ev_property_notify(), for
  performance.
Feature #65: Auxiliary window detection

- Add auxiliary window detection (--detect-transient &
  --detect-client-leader). Thanks to SmilingHorse for inspiring me. The
  implementation is not too speed-efficient, and bugs are to be
  expected.

- Known issue: auxiliary window detection may not work too well with
  windows that are never mapped, for example as client leader.
Misc: Code cleanup

- Move some long functions to ./src/compton.c .

- Fix a small potential issue in win_set_focused() when a window with
  neither leader nor client window is focused.

- Add DEBUG_LEADER.
Feature #69: Blur window background

- Add window background blur support (--blur-background &
  --blur-background-frame), with X Render convolution filter.
  The performance sucks. The performance when the window is opaque but
  frame is transparent could be improved, but there are two possible
  ways and I'm hesitating.

- Known issue: The blurring effect looks very ungraceful during fading.
  I could partially fix the problem, but it probably isn't easy to fix
  it completely.
Improvement: Dynamic blur strength & improved frame blur performance

- Remove the region expansion design in win_blur_background(). I must be
  sleep-walking when I wrote that!

- Improve performance of blurring when a window is opaque but its frame
  is transparent.

- Adjust blur strength according to window opacity.
  --blur-background-fixed restores the old behavior.

- Add "use_offset" parameter to a few functions for convenience. Code
  clean-up.
Misc: Documentation update

Update man page and README.