Additional JEPs for JDK 8 M6

[mark.reinhold at oracle.com]

I've targeted the following JEPs to JDK 8 M6 and updated the milestone
and feature pages [1][2] accordingly:

  138 Autoconf-Based Build System
  142 Reduce Cache Contention on Specified Fields
  143 Improve Contended Locking
  147 Reduce Class Metadata Footprint
  148 Small VM
  149 Reduce Core-Library Memory Usage
  155 Concurrency Updates (jsr166e)
  161 Compact Profiles
  162 Prepare for Modularization
  165 Compiler Control
  166 Overhaul JKS-JCEKS-PKCS12 Keystores
  170 JDBC 4.2
  171 Fence Intrinsics
  172 DocLint

Work on these JEPs has been underway, to varying degrees, for some time,
so there shouldn't be many surprises here.

- Mark


[1] http://openjdk.java.net/projects/jdk8/milestones
[2] http://openjdk.java.net/projects/jdk8/features