Extracted all "shapely" dependencies into module aagen.geometry.
All other modules now have no explicit dependency on Shapely, although they may still
reference some fields of Shapely objects (to be cleaned up later).

Squashed commit of the following:

commit b8cbc144a7c1f2c013a549dbc7fae54114c474f1
Author: Glenn Matthews <glenn@e-dad.net>
Date:   Tue Oct 15 16:14:55 2013 -0400

    Created geometry.minimize_line()

commit d38eec9c05c0baff23b468af21c7fd9f914f4854
Author: Glenn Matthews <glenn@e-dad.net>
Date:   Tue Oct 15 15:48:15 2013 -0400

    Fixed an issue with connection construction relative to rectangular rooms

commit ca5f178c19e09f8f2c1b9007abc61d170f22139d
Author: Glenn Matthews <glenn@e-dad.net>
Date:   Tue Oct 15 15:32:41 2013 -0400

    Fixed boneheaded error in rectangle_set()

commit a9ac68c83c84d9cc5e5c456395bce59f764cba33
Author: Glenn Matthews <glenn@e-dad.net>
Date:   Tue Oct 15 15:30:19 2013 -0400

    Added CoordinateSequence support in to_string(), fixed bug in rectangle_set()

commit 97a14ae497faf9ab0f7740b2230b81da6850bd37
Author: Glenn Matthews <glenn@e-dad.net>
Date:   Tue Oct 15 15:29:38 2013 -0400

    Removed code forcing unusual rooms

commit 8776f282154dd6b1da8fd87e6407e10e2e50bed1
Author: Glenn Matthews <glenn@e-dad.net>
Date:   Tue Oct 15 15:20:12 2013 -0400

    Removed LineString dependencies from Map

commit 0f5dfaec1535dc3cc893225bc33b3004879b53ca
Author: Glenn Matthews <glenn@e-dad.net>
Date:   Tue Oct 15 15:17:18 2013 -0400

    Created geometry.union(), removing cascaded_union dependency from Map

commit da26e7a3830c90126f2a5ed005b409e83246ce0d
Author: Glenn Matthews <glenn@e-dad.net>
Date:   Tue Oct 15 15:09:53 2013 -0400

    Created geometry.line_loop(), removed LinearRing dependency from Map

commit c13c7f5e5f804f85c84e3da04e5b71e0129d7133
Author: Glenn Matthews <glenn@e-dad.net>
Date:   Tue Oct 15 15:03:21 2013 -0400

    Created geometry.lines_to_coords(), removed MultiLineString dependency from Map

commit 959bc6760d17a60ec5a6bc9dfb8b45b190d26a00
Author: Glenn Matthews <glenn@e-dad.net>
Date:   Tue Oct 15 14:52:15 2013 -0400

    Created geometry.differ(), fixed bug in trapezoid generation

commit 022062862a11d4b9191d0367c26e6df1c28f5687
Author: Glenn Matthews <glenn@e-dad.net>
Date:   Tue Oct 15 14:34:10 2013 -0400

    Created geometry.intersect() method, used in find_options_for_connection. See #21

commit e6265755d51e72e0e0ce6ffbaf5a53f9bb533ffc
Author: Glenn Matthews <glenn@e-dad.net>
Date:   Tue Oct 15 14:22:30 2013 -0400

    Fixed error in to_string, fixed linemerge issue similar to #21

commit 95cd408b0489824d66dae50f0d30cf43c2ec8985
Author: Glenn Matthews <glenn@e-dad.net>
Date:   Tue Oct 15 14:00:07 2013 -0400

    Moved rotate() from map to geometry, various other minor fixes

commit ca7fb518607c082617303462a35be9f83989a5b2
Author: Glenn Matthews <glenn@e-dad.net>
Date:   Mon Oct 14 15:38:59 2013 -0400

    Moved trim_to_fit() into geometry module

commit d68ed76832a9f683bb3197b473e7b1028d4fb3a6
Author: Glenn Matthews <glenn@e-dad.net>
Date:   Mon Oct 14 14:48:05 2013 -0400

    Removed Point dependency from map

commit 6049ca1d2a12078dd22beb410e9eef50dc9a942e
Author: Glenn Matthews <glenn@e-dad.net>
Date:   Mon Oct 14 14:40:16 2013 -0400

    moved bounds_str() to geometry

commit 934cc9081561b1544704641286a54ca65e2617cb
Author: Glenn Matthews <glenn@e-dad.net>
Date:   Mon Oct 14 14:39:40 2013 -0400

    Removed shapely dependencies

commit 0b646e86da43f56fa13993d4f1ee99ca96fe036b
Author: Glenn Matthews <glenn@e-dad.net>
Date:   Mon Oct 14 11:10:30 2013 -0400

    Removed more shapely dependencies from map.py

commit c6f14d14259325e0847e95ec0f574ec2dea38d69
Author: Glenn Matthews <glenn@e-dad.net>
Date:   Mon Oct 14 11:01:07 2013 -0400

    Extracted sweep_corner() from Region class to Geometry module

commit 7e8d23d4d2dd3d38131bb7649ec3ece47e17f440
Author: Glenn Matthews <glenn@e-dad.net>
Date:   Mon Oct 14 10:31:54 2013 -0400

    Removed last shapely reference

commit 68110794c14ec667648f6a8d57b613fc3433fe79
Author: Glenn Matthews <glenn@e-dad.net>
Date:   Mon Oct 14 10:28:28 2013 -0400

    Removed poly_to_str() from map.py

commit e8ee35f15e30aedcc7428d64c204eb4e17002718
Author: Glenn Matthews <glenn@e-dad.net>
Date:   Mon Oct 14 10:07:37 2013 -0400

    map no longer needs explain_validity but geometry now does

commit 30bc92bf1adbe39b1aec121bddef4e3f01d5b765
Author: Glenn Matthews <glenn@e-dad.net>
Date:   Mon Oct 14 10:02:38 2013 -0400

    Extracted Direction to its own module, extracted sweep() and polygon_between_lines() from Region class into Geometry module as sweep() and loft()

commit 1d1c7f8ffb66e9d71c2cb5c76791aba0686a66ae
Author: Glenn Matthews <glenn@e-dad.net>
Date:   Fri Oct 11 17:05:21 2013 -0400

    Migrated unusual room generators to geometry