Use shaded asm classes provided by Kryo.

Recent versions of Kryo have bumped the asm dependency to 4.X
which conflicts with many other libraries (including some Hadoop
versions) that use asm 3.X.

Presumably to help with this, Kryo now bunldes a shaded version
of asm inside of its own jars. This patch alters chill to use
Kryo's shaded asm package.

If Kryo stops shading this in future versions or changes
the shaded package name, this can easily be changed
accordingly or reverted to vanilla asm.
Merge pull request #175 from pwendell/asm

Use shaded asm classes provided by Kryo.