netlogo applets in Windows can't use paths

NetLogo applets running in Windows incorrectly convert 
the "/" in the path part of a url to "\".

So add a hack to the Makefile to copy data-export-modular.nls
to the same directories the main NetLogo models are located.

Also tell git to ignore the resulting copied files.

Example:

This is the url for an http request sent by a NetLogo applet
running in Windows for a resource.

http://visual.concord.org/experiments/netlogo-visual/models/..\..\netlogo-modules\data-export-modular.nls
Update atom gradients during repaint / reset operations

[#47122043]
Add a new view option: markColor

[#46394263]

It defines color of marked atoms.
Update MML->JSON conversion tests due to new markColor option

[#46394263]
Update "Mark Atom" interactive, let user select mark color

[#46394263]
Bump vows version to 0.7.0

0.6.2 versions seems to have problems with Node.js v0.10.1
Use assert.lengthOf to assert.equal in tests due to performance

assert.lengthOf was taking hours after vows (or node.js) update.
initial diffusion across semipermeable membrane interactive
textBox: rotate, strokeWidth, strokeOpacity

[#47150443]

TODO: determine if +Java MW supports any of these
attributes and if so import them properly
textBoxes examples: rotated, without frame stroke

[#47150443]
more consistent language in dipole dipole interactive

[#47147807]
textBoxes examples: rotated 180 with fill

[#47150443]
textBox: use accurate rotation label

[#47150443]
textbook: full width example (not working)

[#47150443]
textbook: rotated wrapped example (not working)

[#47150443]
textBox: fontScale, rotated-wrapped, full-width

[#47150443]
improve Invalid Model URL error
TextBox: support optional height attribute

[#47150443], [#47151541]

See added "larger frame" textBox examples
textBox: example using optional strokeWidth

[#47150443]

Also reposition examples to make them easier to distinguish.
rename externalFx -> externalAx

Classic MW defines externally-applied forces on obstacles per mass unit, so they're really accelerations.

[#45325343]