Cleanup o.a.j.mk from oak-core

As hinted in [1] the o.a.j.mk packages in oak-core must be cleansed:

(1) Empty packages to be removed:
o.a.j.mk.api
o.a.j.mk.blobs
o.a.j.mk.json
o.a.j.mk.model
o.a.j.mk.store.persistence
o.a.j.mk.util

(2) Other packages:
o.a.j.mk --> MK factory does not belong here ([2])
o.a.j.mk.client --> Same .server: separate project (maybe same as .server; maybe not..)
o.a.j.mk.fs --> FS abstraction ? Remove ? or move to separate project
o.a.j.mk.index --> related to mk.simple; duplicate stuff ??
o.a.j.mk.server --> Separate project. This is stuff specific to standalone setup
o.a.j.mk.simple --> MK implementations seems to be partly duplicate; remove here; move to separate project
o.a.j.mk.wrapper --> wrappers belong to MK or separate modules; plus separate package per wrapper type

I really think this should be done as soon as possible, hense I mark this as to be fixed for the 0.2 release.

[1] https://issues.apache.org/jira/browse/OAK-24?focusedCommentId=13231255&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-13231255
[2] http://oak.markmail.org/thread/j34cd5m6ti5nwuit