Add CVPixelBuffer support to visualize command

Summary: I often run this three-liner to `visualize` a `CVPixelBuffer` so figured we could save some time by building it into the `visualize` command.

Differential Revision: D22653607

fbshipit-source-id: bf03acb4e091b8c93b7e1c73ea8b065755c706ad

Make chisel compatible with Python 3 (#266)

* Make chisel compatible with Python 3

Xcode 11 shipped with Python 3 now. Unfortunately, chisel was written in
Python 2 style and will fail load for lldb. This PR fixed the Python 3
compatibility issues.

* Addressed comment. Updated with file output.

* Properly resolve the conflict.

* Import from future on print.

* Address @lsavino comment.

Merge pull request #251 from facebook/legacy-build

Use Legacy build system

Merge pull request #235 from facebook/heapfrom

Add heapfrom command

Merge pull request #218 from facebook/xcode-share-chisel-scheme

Share the Chisel scheme

Merge pull request #216 from facebook/findinstances-command

Implement findinstances command

Merge pull request #202 from facebook/visualize-casts

Add CGFloat casts to fix visualize command

Merge pull request #168 from facebook/no-trap-exceptions

Evaluate with SetTrapExceptions set to False

Merge pull request #135 from kolinkrewinkel/master

Use correct UI/NSResponder class in presponder (fixes #134)

Merge pull request #117 from idrisr/master

Use base10 value for ivarOffset to be consistent with other values used