wmitime: Allow -display option with no argument

Previously, if a user ran wmitime with the -display option and no argument,
a segmentation fault would occur. Print a warning instead.

Patch from Debian [1] to fix bug #716466 [2].

[1] http://sources.debian.net/src/wmitime/0.3%2B20120605-1/debian/patches/allow_display_with_no_args.patch/
[2] https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=716466
wmitime: Update Makefile.

In particular,
- Remove reference to deprecated X11R6 directory.
- Replace FLAGS variable with CFLAGS, CPPFLAGS, and LDFLAGS.
- Honor CC, PREFIX, and DESTDIR variables.
- Use INSTALL instead of cp for installation.
- Remove redundant -lXext flag.
- Move contents of wmitime directory to top directory to ease the building
  process.

Inspired in part by the Debian patches [1,2].

[1] http://sources.debian.net/src/wmitime/0.3%2B20120605-1/debian/patches/20-makefile-CC.patch/
[2] http://sources.debian.net/src/wmitime/0.3%2B20120605-1/debian/patches/make-install.patch/
wmitime: Improve locale support.

Previously, wmitime only had support for English, French, and (in Debian
only) Hungarian.  In addition, the choice was made at compile time.

This patch adds run-time support for any language using the Latin alphabet.
The locale is determined by the user's environment or may be specified on
the command line with the "-l" option.  Note that users whose environment
specifies a non-Latin locale may wish to use, e.g., "-l C", as otherwise
no date will appear.

Note that, for simplicity, the month and day are now displayed as "01 JAN"
as opposed to "JAN 01".  (Previously, the former format was used for English
and the latter for French.)
wmitime: Remove C++ style comments.
wmitime: Remove references to config file in source; nonexistent feature.
wmitime: Update contact information.
wmitime: Add manpage.

Adapted from Debian [1].

[1] http://sources.debian.net/src/wmitime/0.3%2B20120605-1/debian/wmitime.1/
wmitime: Add desktop file.

Adapted from Debian [1].

[1] http://sources.debian.net/src/wmitime/0.3%2B20120605-1/debian/wmitime.desktop/
wmitime: Remove wmitime-master-led.xpm; unused duplicate file.
wmitime: Do not include or compile unused wmgeneral files.
wmitime: Bump to version 0.4.