Initial implementation of a metaprogramming function, that is capable of detecting element index in variant::types. Some tests to make sure that no old valid code was broken
Started the work on polymorphic_get to determinate sanity/safety of getting Base type. Fixed an issue with polymorphic_get<const final>. More tests, added safe_get and unsafe_get methods. Minor update of the docs
Make polymorphic_get U type  compile time checked, add more tests and improve docs. Use strict as a default policy for polymorphic_get and get (as recomended at mailing list discussions)
Apply naming recomendations from mailing list discussion: unsafe=>relaxed, safe=>strict
Merge branch 'master' into develop
Avoid some non essential hard for compilers tests, improve tests coverage
Improve tests coverage: add tests to ensure varinat is in correct state after exception in assignment of move assignemnt functions; make sure that recursive varinats swap and assign well
Another attempt to improve tests coverage
Minor improvement to the autotest script
Throw exceptions on specified assignment numer N in variant_nonempty_check and make tests run on a multiple different Ns
Fixed a bug with copy constructing a backup holder; changed some tests
Make the variant_nonempty_check check variant behavior on different internal policies: with/without fallback type + throw/nothrow copyable + throw/nothrow movable