Fix selecting languages not supported by Windows locale

Spotted for Russian under an English Windows environment.

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/r-temis@533 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
Check for invalid characters on import

Selecting the wrong encoding is a very common mistake,
and without this check users get weird errors which do not
indicate that encoding is the issue at all.

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/r-temis@534 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
Show encoding suggestions based on language on import

Also update translations.

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/r-temis@535 edb9625f-4e0d-4859-8d74-9fd3b1da38cb