- move triggers (BB/Win/OSX) to before_script section
- update DROPBOX_KEY for windows
- copy archive binaries to dropbox
- do not use custom lcov. just use ctest -ExperimentalCoverage
- OSX sed expects parameter for "-i" option
- for Windows and OSX build, we need to get the commit hash of HEAD~
instead of HEAD because we made an extra commit to trigger the build