Clean up install class

The install class seems to be designed to make the logic decision on how
to install r10k based on whether or not PE is being used. However, some
of that logic had leaked out into the init.pp file, and the install/*.pp
classes were redundant in many ways. This commit simplifies and reduces
the apparent complexity of the class without changing the functional
configuration.
Add back 0.0.9 support (make, gcc)

There are currently bugs in r10k 1.x which make using 0.x desireable
in certain circumstances. However, 0.x requires make and gcc.
Conditionally include those classes if necessary due to 0.x r10k version
usage.

When 1.x is just as good or better than 0.x, we can stop supporting
0.x and remove these bits.

Conflicts:
	manifests/install.pp
Merge pull request #6 from reidmv/decomplexify_install_class

Clean up install class