Sanitize `state_dims` before use as loop variable

The overloaded `inspector` method in `RigidBodyWRLVisualizer` was
passing `state_dims` to the parent method as a row vector. The method in
`Visualizer` was then transposing that before using it as the loop
variable in a for loop. Since for loops loop column-wise, I've replaced
the transpose with a reshape to ensure that the variable passed to the
for loop is a row vector. Fixes #23.
Add class `RigidBodyVisualizer`.

Now both `BotVisualizer` and `RigidBodyWRLVisualizer` descend from this
class. It contains the nicely overloaded inspector method that respects
joint limits (this used to be in `RigidBodyWRLVisualizer`).
Makes cmake run from the drake main directory to fix an issue where it would fail if run from the wrong path.  Specifically fixes an issue with AVL configuration.
Fixed a small type error
use fullfile instead of /
Merge branch 'fix-inspector' of https://github.com/avalenzu/drake