Add optional boolean type

[okt-yurijp]

Add optional boolean type and helpers for it.

[ol-arteman]

We do already have te_bool3 type with three values and a job opt wrapper for it TAPI_JOB_OPT_ENUM_BOOL3. So I'd like to see any rationale why we need another type with basically the same semantics. Or e.g. why we should abandon te_bool3 in favor of te_optional_bool_t

[okt-yurijp]

Sorry for great delay in anwer(
We use this type in our new suite together with te_optional_uint_t type. And in package.xml we use value "-" for both of these types.
Now, if we switch to te_bool3 we have 4 options:

1. Substitute "-" value to "UNKNOWN". But it looks a little bit ugly: in one place we use "-" for optional int and in another place we need to use "UNKNOWN" in the same meaning for te_bool3.
2. Add parser of "-" value in our suite only. But may be it can be useful for other suites too.
3. Add additional parser of "-" value to TE for te_bool3 type.
4. Use this patch with te_optional_bool_t

Which option do you prefer?

[ol-arteman]

Sorry for great delay in anwer( We use this type in our new suite together with te_optional_uint_t type. And in package.xml we use value "-" for both of these types. Now, if we switch to te_bool3 we have 4 options:

1. Substitute "-" value to "UNKNOWN". But it looks a little bit ugly: in one place we use "-" for optional int and in another place we need to use "UNKNOWN" in the same meaning for te_bool3.

2. Add parser of "-" value in our suite only. But may be it can be useful for other suites too.

3. Add additional parser of "-" value to TE for te_bool3 type.

4. Use this patch with te_optional_bool_t

Which option do you prefer?

I am definitely for option (3).

[okt-dmitriyb]

Created new PR with (3)
#96