xca.ico is only used as resource of the EXE file. To make
that work, the linker option -MD is necessary.
Use the 128x128 px PNG in favor to the 128x60 px PNG
as icon to avoid rescaling.
Don't use the xca.ico, which would require "imageformats/qico.dll"
This also reverts the rubbish commit 583b9f82b2.
Improve Windows installation xca.wxs
Move documentation to "html" dir and translations to "i18n"
in the portable-app and the MSI installation
Modyfies getDocDir() and Introduces getI18nDir()
Drop Nullsoft installer files
