Bug fixes and other changes
* build context in release build
* make consistent build context for py versions
* Revert "Update build context on 1.4.1 EI dockerfiles (64)"
* a typo in build_all script
* Update build context on 1.4.1 EI dockerfiles
* correct typo in buildspec
* enable PR build
* separate pip upgrade from other installs
* New py2 dlc dockerfiles
* New py3 dlc dockerfiles