Add a new submodule: lab-grapher

It's code extracted from the Lab repo itself.
Use grapher code from the submodule instead of src directory

[#61295834]
Remove grapher code (some files were unused even by grapher itself)

[#61295834]
Merge branch 'master' into grapher-submodule

Conflicts:
	.gitmodules
Remove grapher tests (they are already moved to lab-grapher repo)

[#61295834]
Fix tests config (they pass now)

[#61295834]
Update lab-grapher submodule
_grapher.sass ➙ _bar_graph.sass :  it defines bar graph styles only

bar-graphs are defined in the lab project, and have no lab-graph reps.
The SASS should be named accordingly.

[#61295834]
https://www.pivotaltracker.com/story/show/61295834
Use Sass CSS Importer Plugin to combine lab-grapher css file into lab.css

Here’s the link to the sass plugin: http://bit.ly/1fqXQk1

[#61295834]
https://www.pivotaltracker.com/story/show/61295834
Remove sass-importer plugin, its a bit raw.

[#61295834]
https://www.pivotaltracker.com/story/show/61295834
grapher.build.js, lab.build.js &etc.: + Require paths lab-grapher.

[#61295834]
https://www.pivotaltracker.com/story/show/61295834
public-api.js : export Lab.grapher.Graph

[#61295834]
https://www.pivotaltracker.com/story/show/61295834
Fix lab-grapher submodule reference.
Merge branch 'master' into grapher-submodule

# By Aaron Unger (18) and others
# Via Piotr Janik
* master: (28 commits)
  Change triple bond symbol from =- to # (more similar to SMILES notation)
  Update "Catalysis" interactive (display help tips on load)
  Update "Catalysis" interactive
  Add "Randomness Example" interactive
  Set random seed based on the model time
  Do not repaint the whole container when text box is updated
  Improve tick history support in .callEvery() and .callAt() functions
  Fix rendering of atoms' marked state
  ITSI: Fix button text in Electrostatics 4
  ITSI: Electrostatics 5 interactive
  ITSI: Electrostatics 4 interactive
  ITSI: Fix Explosion model 2
  ITSI: Fix Limiting Reactions
  Sort the ITSI interactive groups alphabetically
  ITSI: Fix Chemical Reactions 2
  ITSI: Fix Mixing Polar and Non-Polar
  ITSI: Fix aspect ratio on What is a Salt?
  ITSI: Fix Chemical Reactions 6
  ITSI: Fix Getting Ratios Right
  ITSI: Fix Ammonia Molecules
  ...

Conflicts:
	.gitmodules
	test/requirejs-config.js
remove lab-grapher submodule
Move lab-grapher submodule into vendor.
(continued) rename submodules/lab-grapher ➙ vendor/lab-grapher
Merge branch 'master' into grapher-submodule

* master:
  Add new interactive option ('randomSeed') to control randomness