Bump program version to 0.3.
Prepare ChangeLog for release v0.3.
Fix missing colon in help output.
Refresh German translation from template.
Fix missing linker flags for libintl.

Autoconf provides the correct -l flags for libintl and libiconv in
@LIBINTL@, so include that when constructing _LDADD variable.
Display program name in --version output.

Switch from PACKAGE_VERSION to PACKAGE_STRING for argp global.
Merge branch 'release-0.3' into develop