Unicode update of width and other character properties

[Thomas Wolff <towo at towo dot net>]

Hi,
this is a proposal to update wcwidth and the character properties 
functions isw*/towupper/towlower to Unicode 10.0, as discussed in the 
mail thread https://cygwin.com/ml/cygwin/2017-07/msg00366.html,
as well as to simplify automatic generation of respective tables for an 
easier update step.
Table size is moderate (using ranges for character properties) but there 
is still an option to reduce the two big tables in size.

The patch can be retrieved from http://towo.net/cygwin/charprops10.zip .

The Makefile.widthdata does not yet distinguish the two subdirectories
(libc/string, libc/ctypw) as it comes from a common development directory.

There is a test program in which comparison for isw*/tow* functions
between current and patched implementation can be compared.

I also provide a log of deviations of the new approach to the current 
implementation, based on Unicode 5.2 data, to compare and check.
If there are any disputable cases, I would consider that of course.

My main aim was actually to get the wcwidth data updated, for which the 
change is more obviously clear.

Thanks
Thomas