Docs not clear about support of empty containers

[yves.pausch@…]

The reference docs make no statement about the validity of empty tuples or arrays. Only one place makes an implication: “Sequences are data structures that merge the properties of both lists and tuples with the exception that a seq cannot be empty.” - the implication being that lists and tuples (and thus by extension arrays) _can_ be empty.

The docs should mention that empty tuples/arrays are not supported and also for what reason they are not supported.

Due to a change of behavior along with release 1.49 as stated in #6760 I'm convinced a statement is overdue.

[Edward Diener]

The docs have been updated in the 'develop' branch of the preprocessor library, in the documentation for each data type, to explain that arrays and lists can be empty, and thereofore have 0 size, but that seqs and tuples cannot be empty and therefore have a minimim size of 1.

[Edward Diener]

This has now been fixed in the latest Boost 1.59 release.