Port to gtk3
Don't set AM_CFLAGS in configure.ac

This is bad form. AM_CFLAGS are only meant to be set in Makefiles.
Remove obsolete AM_CFLAGS
Add --enable-minimal-flags switch

This is useful for strict source distros.
Fix build with clang
Fix error handling in poll_cb()

Clang correctly reports this as a problem:
  "use of logical '||' with constant operand"

I'm not sure what the compiler actually does here if we
omit the second "stat ==", so just fix it.
Fix ignored CFLAGS
Fix signed/unsigned int comparison
Fix missing field initializer
Fix deprecation warning for gtk+3-3.12
use execvp to support mixer programs with arguments
fix invisible icon on gtk3
- tray_icon has to exist before prefs are applied for correct icon
- gtk_status_icon_is_embedded returns false until the prefs window is opened on gtk3 for some reason
fix spelling mistake (aquire_hotkey -> acquire_hotkey)
...still didn't fix the hotkey issue though :)
didn't need that extra gchar**, oops!
Fix keybindings
exit gracefully from the menu
IMO "ERROR 208" return value isn't graceful! It closes down properly now, return 0.
Merge branch 'stevenhoneyman-gtk3' into gtk3
Fix -Wparentheses compiler warning
missed a set of brackets - oops!
Fix white color volmeter