Updated test framework to R2014b-PR
Scatter plots in R2014b

Scatter plots in R2014b (HG2 objects) use different objects which weren't
handled properly.
R2014b: HG2 Group objects handled
handleAllChildren: useful warning when no children

If handleAllChildren was called but no children were present, an obscure
error was returned (bad SWITCH statement) due to children returning []
and hence their type being [] while a string is expected.
So now, [] is being cast to char and the case '' is handled explicitly.
Stem and Stair plots in R2014b
Annotations: Ellipses

First Step to support Annotations: Ellipses.
strcmp[i](..., 'none') -> isNone

Used `isNone` everywhere.
R2014b bar objects

Mostly handled, only the colors remain way off.
For now, just the structure will have to suffice, as finding the "flat" color
(which is interpreted in the colormap) is not as straightforward as expected.
R2014 error bars
R2014b area fixed, "flat" color mode fixed
Quiver R2014b added

In R2014b, the line series with explicit coordinates is no longer present.
This means that it was necessary to re-implement the scaling algorithm of MATLAB
Consequently, the previous shortcut has been removed, making sure that the code
base is equivalent for the different versions of MATLAB.

The output from the ACID tests (23 and 25) looks fine from R2014b. Older
versions have not yet been tested, that will happen right before merging this
branch into master
empty str in handleAllChildren
Merge pull request #355 from LJeub/master

Fix bug for colormaps with only 1 colour
Contour plot: basic principles

Basic contour plots are working, except for:

 - color information
 - filled contour plots are not supported
   by pgfplots, so we will need a work-around
   (e.g. use patches instead or plot some kind of surf
   beneath it)
 - 3D contours are not yet supported
Legends implemented
R2014b colorbar support

The support is a bit hacky, but seems to work OK
Tests fixes for colorBarLog, pixelLegend

 colorBarLog -> not supported on R2014b
 pixelLegend -> set units on legend itself
Test: double_axes fixed for R2014b

Children of a figure may also include other things (e.g. menus).
Now looking for axes explicitly
Merge branch 'R2014b'

Basic support for MATLAB R2014b.

Not working is:

* Contour plots do not account for the selected color map at the moment
* Filled contour plots are replaced by unfilled ones
  (as pgfplots only supports the latter and R2014b supplies insufficient data
  to manually build a contour plot without more intricate work)
* Logarithmic color bars (test case 18) are handled as linear ones
  (as far as I know these were never a documented MATLAB feature)
* test `80`: the abs text is missing.
* Clipping in 3D plots (e.g. tests `[67 70]`) is changed in MATLAB R2014b.
  We still use the old one (and disregard options to change it)
* In test cases `[15 16 36 91]` there are some objects that are handled with
  production of warnings. The output, however, looks reasonable.
Document different paths variables

External documentation for the different path variables.
Kept outside of the main branch (for now), to not clutter
end-users installation