REGION: make strings translatable.

Signed-off-by: bert <bert.timmerman@xs4all.nl>
REGION: check for NULL pointers and do basic checks.

Signed-off-by: bert <bert.timmerman@xs4all.nl>
3DFACE: corrections in messages.

Signed-off-by: bert <bert.timmerman@xs4all.nl>
3DSOLID: corrections in messages.

Signed-off-by: bert <bert.timmerman@xs4all.nl>
ACAD_PROXY_ENTITY: corrections in messages.

Signed-off-by: bert <bert.timmerman@xs4all.nl>
APPID: corrections in messages.

Signed-off-by: bert <bert.timmerman@xs4all.nl>
ARC: corrections in messages.

Signed-off-by: bert <bert.timmerman@xs4all.nl>
ATTDEF: corrections in messages.

Signed-off-by: bert <bert.timmerman@xs4all.nl>
ATTRIB: corrections in messages.

Signed-off-by: bert <bert.timmerman@xs4all.nl>
BLOCK: corrections in messages.

Signed-off-by: bert <bert.timmerman@xs4all.nl>
BODY: corrections in messages.

Signed-off-by: bert <bert.timmerman@xs4all.nl>
CIRCLE: corrections in messages.

Signed-off-by: bert <bert.timmerman@xs4all.nl>
CIRCLE: added test for correct linetype in dxf_circle_write().

Signed-off-by: bert <bert.timmerman@xs4all.nl>
CLASS: corrections in messages.

Signed-off-by: bert <bert.timmerman@xs4all.nl>
COLOR: corrections in messages.

Signed-off-by: bert <bert.timmerman@xs4all.nl>
COMMENT: corrections in messages.

Signed-off-by: bert <bert.timmerman@xs4all.nl>
DIMENSION: corrections in messages.

Signed-off-by: bert <bert.timmerman@xs4all.nl>
DIMSTYLE: corrections in messages.

Signed-off-by: bert <bert.timmerman@xs4all.nl>
ELLIPSE: corrections in messages.

Signed-off-by: bert <bert.timmerman@xs4all.nl>
ENDBLK: corrections in messages.

Signed-off-by: bert <bert.timmerman@xs4all.nl>