Migration to HG

The NSPR, NSS and related projects have stopped using Mozilla'a CVS server, but have migrated to
Mozilla's HG (Mercurial) server.

Each project now lives in its own separate space, they can be found at:
https://hg.mozilla.org/projects/nspr/
https://hg.mozilla.org/projects/nss/
https://hg.mozilla.org/projects/jss/
https://hg.mozilla.org/projects/python-nss/

This migration has been used as an opportunity to change the layout of the
source directories.

For NSPR, "mozilla/nsprpub" has been removed from the directory
hierarchy, all files now live in the top directory of the NSPR
repository.

Likewise for NSS and JSS, "mozilla/security" has been removed and files
now live at the top level. In addition for NSS, we have merged the
contents of directories mozilla/dbm and mozilla/security/dbm into the
new directory lib/dbm.

Besides the new layout, the build system hasn't changed. Most parts of
the NSS build instructions remain valid, especially the instructions
about setting environment variables.

Updated instructions for building NSS with NSPR can be found at:
/docs/NSS_reference/Building_and_installing_NSS/Build_instructions

It's best to refer to the above document to learn about the various
environment variables that you might have to set to build on your
platform (this part hasn't changed).

However, below is a brief summary that shows how to checkout the
source code and build both NSPR and NSS:
mkdir workarea
cd workarea
hg clone https://hg.mozilla.org/projects/nspr
hg clone https://hg.mozilla.org/projects/nss
cd nss
# set USE_64=1 on 64 bit architectures
# set BUILD_OPT=1 to get an optimized build
make nss_build_all

Note that the JSS project has been given a private copy of the former
mozilla/security/coreconf directory, allowing it to remain stable,
and only update its build system as necessary.

Because of the changes described above, we have decided to use a new
series of (minor) version numbers. The first releases using the new code
layout will be NSPR 4.10 and NSS 3.15