#303 Add boolean class and category for USAGE BIT items / boolean literals

[Simon Sobisch]

While cobc/tree.h has

CB_CLASS_BOOLEAN,       /* 3 */

and

CB_CATEGORY_BOOLEAN,            /* 4 */

cobc actually doesn not use these internal as it should be - they are only used for internal boolean yes/no values. Boolean literals for example are handled as numberic class and category in scanner.l.

Relates to bitwise operations [feature-requests:#235] - for not numeric items.

[Simon Sobisch]

Parsing of USAGE BIT / PIC 1 added with [r2548].

[Simon Sobisch]

For a testcase see the related (duplicate) FR.