Finer Gap Filling until Medial Axis is used.

These gap filling settings almost completely fill even the finest gaps.

tested in printing and they work well.

my @widths = (1.5 * $w, $w, 0.5 * $w);  # worth trying 0.2 too?
            
![image](https://f.cloud.github.com/assets/203922/273454/b95f31a4-9024-11e2-987c-5c45c7f844a8.png)

I know you said 1.5 is worth using, but I can not find a test case where it actually gets used.  And why would it? anything 1.0 and larger gets filled with a single perimeter.

here is what I was using which works better
commit: f18f2782fc0b29f091e020595555c70e58e654c0
my @widths = (0.6 * $w, 0.3 * $w, 0.1 * $w);  # worth trying 0.2 too?

![image](https://f.cloud.github.com/assets/203922/273483/eaaae270-9025-11e2-89fe-3b3ab4c6c332.png)

And here are the settings that I find to be the best at not leaving little holes between sizes (though you could probably leave off the 0.004 as that ends up being more a "stitching" action than an actuall filling:

commit: 768d410a2eff577cd8f8051200792b0fe95ba386
my @widths = (0.4 * $w, 0.04 * $w);

![image](https://f.cloud.github.com/assets/203922/273492/3a1511a0-9026-11e2-9ae4-4639c0d89f21.png)