LeftTerminator and RigthTerminator generalized for Unicode. Refs: #75.
Same rule (~Strings.IsIdent) used in both cases.
Two separate functions retained in the code for preserving
the program structure and for easily allowing asymmetric rules
if there should arise any need in the future.

Width of option labels increased in the dialog as proposed in CPC 1.7 rc5.

Signed-off-by: Josef Templ <josef.templ@gmail.com>