Export version as version_core and update package version (tensorflow…

…#856)

Turn off WEBGL_get_buffer_sub_data_async. (tensorflow#849)

Update version to 0.6.0-alpha4

update version to 0.6.0-alpha3

update version to 0.6.0-alpha2

Update version to 0.6.0-alpha (prerelease)

update version

version 0.5.0

save

update version to 0.4.1