Bump package versions for 1.6-beta.15 release.

Bump package versions for 1.5.2-beta.7 release.

Bump package versions for 1.6-beta.14 release.

Bump package versions for 1.5.2-beta.6 release.

Bump package versions for 1.6-beta.13 release.

Bump package versions for 1.6-beta.12 release.

Bump package versions for 1.6-beta.11 release.

Bump package versions for 1.5.2-beta.5 release.

Bump package versions for 1.6-beta.10 release.

Bump package versions for 1.5.2-beta.4 release.