Revert "[maven-release-plugin] prepare for next development iteration"

This reverts commit 12e237e4bc8a307db3b823d8705cb1e28569c461.
Revert "[maven-release-plugin] prepare release v0.9.1-rc1"

This reverts commit 81c6a06c796a87aaeb5f129f36e4c3396e27d652.
[SPARK-782] Made Spark use existing shaded ASM and removed Spark's ASM dependency

This ports the changes in #100 to branch 0.9. However, unlike that PR, it does not exclude ASM from all dependencies of Spark, to ensure compatibility in branch 0.9.

Author: Tathagata Das <tathagata.das1565@gmail.com>

Closes #232 from tdas/asm and squashes the following commits:

999bb6f [Tathagata Das] Made Spark use existing shaded ASM and removed Spark's ASM depedency.