Updated ruby-squib to 0.12.0.

Features:

    save_pdf now supports crop marks! These are lines drawn in the margins of a PDF file to help you cut. These can be enabled by setting crop_marks: true in your save_pdf call. Can be further customized with crop_margin_bottom, crop_margin_left, crop_margin_right, crop_margin_top, crop_marks, crop_stroke_color, crop_stroke_dash, and crop_stroke_width (#123)
    Squib.configure allows you to set options programmatically, overriding your config.yml. This is useful for Rakefiles, and will be documented in my upcoming tutorial on workflows.
    Squib.enable_build_globally and Squib.disable_build_globally are new convenience methods for working with the SQUIB_BUILD environment variable. Handy for Rakefiles and Guard sessions for turning certain builds on an off. Also will be documented in upcoming workflow tutorial.
    The import methods csv and xlsx now return Squib::DataFrame, which behaves exactly as before - but has more cool features like being able to do data.name instead of data['name']. Also: check out data.to_pretty_text. Check out the docs. (#156)

Bugs:

    showcase works as expected when using backend: svg (#179)
    Graphics will get flushed upon exit, so working under Guard with backend: svg is more reliable (#180)

Docs:

    Wrote out documentation for Squib and GameIcons
    Wrote out documentation for Hello World! Dissected
    Un-submoduled our samples and simply embedded them into the docs (e.g. Squib Thinks in Arrays). Lots of cleanup there
    Wrote up Squib in Action, which documents other Squib projects. Ask for yours to be put there!!

Chores:

    Bumped dependency roo to 2.5.1. Nothing that affects Squib users (probably).
    Bumped graphics and text dependencies (cairo to 1.15.3, pango+rsvg et al. to 3.1.0). No new features for us, but some stability improvements.


(wiz)