(idlwave-template): Respect `idlwave-abbrev-change-case'.

(idlwave-template): Respect `idlwave-abbrev-change-case'.
(idlwave-rw-case, idlwave-elif, idlwave-case, idlwave-for,
idlwave-if, idlwave-procedure, idlwave-function, idlwave-repeat,
idlwave-while): respect `idlwave-reserved-word-upcase'.
(idlwave-rw-case): New function.
(idlwave-statement-match): Fixed problem with assignment regexp.
(idlwave-font-lock-keywords): Improved regexp for keyword
parameters.
(idlwave-surround): New argument LENGTH to support padding of
operators longer than 1 char.