Update pypy-1.8

1.7 --> 1.8 in two locations.
Update pypy-1.9

1.7 --> 1.9 in two locations.
Merge pull request #148 from cclauss/patch-6

Update pypy-1.8
Merge pull request #147 from cclauss/patch-7

Update pypy-1.9
Make LD_LIBRARY_PATH
ignore LIBRARY_CONFIG from the environment.
append $LD_LIBRARY_PATH
disabled shared for python-2.7.7 (for reportlab)
Readme: Update Python versions to match compile

Also matches recent updates to https://devcenter.heroku.com/articles/python-runtimes
Update pylibmc to support nested requirements.

The current regex assumes that pylibmc appears at the beginning of a line
(whitespace only precedes it), which is a fair assumption in a single 'flat'
requirements.txt file. However, if you are using nested requirements then
this is not the case - your pylibmc may exist in a sub-directory. This is
very similar to the way in which mercurial is installed if "hg+" is found
in the requirements file (see the /bin/compile script). By insisting that
pylibmc appear at the beginning of the file, it's impossible to fool the
compilation into installing libmemcached (as this script does) by simply
putting the phrase into a comment, which is what you *can* do with 'hg+'.

I've updated the regex to remove the beginning of line restriction. This
means that you can add a comment to a top-level requirements.txt that
will trigger the install, without having to functionally alter your
nested requirements.

e.g. top-level requirements.txt:

    # fake comment to trigger pylibmc script
    # fake comment to trigger hg+ install
    -r requirements/production.txt
Merge pull request #152 from yunojuno/master

Update pylibmc to support nested requirements.
Merge pull request #150 from cclauss/patch-2

Readme: Update Python versions to match compile
Make builds work when BUILD_DIR=/app

When building with either 'git push' or Anvil, BUILD_DIR is set to a
temporary directory (not /app). However, because the prebuilt Python
interpreter has a prefix of /app/.heroku/python baked into it, the
contents of BUILD_DIR need to be temporarily swapped into /app for the
rest of the buildpack to work.

This temporary swapping breaks other buildpack-compatible tools that
set BUILD_DIR=/app. So the fix is straightforward---skip the swapping
in this case.

Also alias bpwatch to a no-op when REQUEST_ID is not set, since this
indicates we're running outside the Heroku environment.