(travis) Multiple fixups to the CI lifted from blead:

(travis) Multiple fixups to the CI lifted from blead:

 - Much lighter CI runs when smoking a PR
 - Revert backout of ODBC firebird testing aa0e82a2
 - Restore and enhance post-success to run a full CPAN install cycle
 - Cut down the amount of APT repos during updates
 - *FINALLY* remove Module::Build::Tiny front-loading
 - Double check M::B::T is not pulled in
 - Peg Module::Install - new versions deps on autodie, which is 5.8.4+
 - Enhance perl sterilization to somewhat work on < 5.12 as well
 - Correctly detect CI on github forks
 - Improve the "Did it really install?" check
 - Better shuffling of the prereq installation order
 - Fix silencer changes (f8200928) which were practically undone by 8b60b921