logchar = UTF-8 and wchar_t free support

[Curt Arnold <ca...@apache.org>]

I've filled in the missing stuff to allow log4cxx to be built using 
UTF-8 for logchar, which I had planned, and to allow log4cxx to be 
build with no use of wchar_t which I hadn't considered (and which 
implies using UTF-8 for logchar).

To build without wchar_t:

ant -Dhas.wchar_t=0

To build with wchar_t support but using UTF-8 for logchar:

ant -Dlogchar=utf8

To force Unix conventions (aka cygwin), but not yet tested

ant -Dis-unix=true

The UTF-8 implementation of transcoder fails several tests, likely 
cases where a logged character can't be represented in the current code 
page, which I will address tomorrow.  However, all the standard witness 
tests pass, so it should be fairly good as long as you limit yourself 
to USASCII.