all.py: make group names lower case

This changes the group names (but not the test names) to be all
lowercase, even in cases where the OpenGL functionality that is being
tested is spelled with capitals. There are a couple of reasons for doing
this.

First, the group names and the file hierarchy are intimately linked;
Many tests rely on auto-discovery to be added to the profile.tests
dictionary, and auto-generated tests are put in all lowercase
directories. That was done to deal with differences between *nix, OSX,
and Windows handling of capital letters. The problem is that now
generated tests and static tests end up in different branches in the
HTML summary (ARB_ham_sandwich vs arb_ham_sandwich).

This could be addressed by changing the generated tests back creating
capitalized group structures, at least for Linux. And while Linux
represents the majority use case for piglit, it is not the only one.
Sometimes piglit might inconvenience users of OSX or Windows if it makes
things better for more people (using /usr/bin/env python2 instead of
/usr/bin/env python for the shbang, for example). These filesystem
incompatibilities are not mere inconveniences, however, because
ARB_foo == arb_foo on OSX and Windows (without the win32 APIs).

So why not change test names too? Well, I think we should, but that
would mean one of two things. First it would mean that the on disk test
name would be different than the name of the test name in the piglit
results, and developers here objected to that. That could be solved by
renaming (moving) ~1500 tests, which was also strongly objected to.
Groups however, can be fixed by just modifying all.py.

Second, this means that there are few chances of collisions on OSX and
Wdinows, since group names should be lowercase.

Signed-off-by: Dylan Baker <dylanx.c.baker@intel.com>
squash! wip: all.py: make group names lower case

Update json version from 2 to 3. This change lowercases all of the group
names in the results.

This should be squashed into the previous patch to ensure there is not
breakage in the series, but is probably easier to review in this form.
all.py: Remove explicit additions of -fbo and -auto

commit c6fc8b36 caused the PiglitGLTest class (which is the primary test
class used in all.py) to automatically add -auto and -fbo when it is
appropriate. This means by having these we're storing data that doesn't
need to be stored.

Signed-off-by: Dylan Baker <dylanx.c.baker@intel.com>