Get rid of the system-specific updatelocales.sh and introduce an
updatepo cmake rule. po files are also updated before creating the mo
files, and we now keep the .pot file (in the po/en directory). To
stabilize the po file creation, file contents are sorted by source
filename.

Update po files in the process.

added explanation why libintl must not belinked under some oses

Hopefully fixed the problem of IRRLICHT_SOURCE_DIR being not considered when a local version of irrlicht is found.

--HG--
rename : Makefile => Makefile.bak