adding OEM buildid:

change to ro.build.version.incremental from ro.build.date=
Merge pull request #72 from nhirata/OEMBuildDate

adding OEM build date for check_versions.sh
Typo of auto_flash_from_PVT.sh
Merge pull request #74 from askeing/master

Typo of auto_flash_from_PVT.sh
add alias for auto_flash_from_PVT; detect gecko file method
Merge branch 'master' of https://github.com/Mozilla-TWQA/B2G-flash-tool