0.2.0:
 * optional blacklisting and whitelisting of windows by ID
 * choice of format for the printed window ID
 * standard command-line options and help text
 * draw text centred on windows
 * works for more types of windows
 * require fewer key-presses on average
 * changed and documented exit codes

0.1.2:
 * fix bug: filters out the wrong windows (those specifying _NET_WM_WINDOW_TYPE
   normal)

0.1.1:
 * only display the remaining characters to type on windows
 * improved window filtering
 * fix for launching from other keyboard-grabbing programs

0.1.0:
 * first release