Add a vtkPath class to represent lines and Bezier curves.

Change-Id: Ie6fd3f46efc1000c517e8386aeda9328bc6307d8
Add API to generate vtkPath data and colored images from MathText.

* Add API to produce a vtkPath representing contours of math text.
* The vtkMathTextUtilities API now accepts vtkTextProperties to
  set colors, font size, etc.
* Make MathTextUtilities abstract (The matplotlib module overrides
  this class in a later commit)
* Remove python dep from vtkMathText.

Change-Id: Id4d9fb91be831673d13b865802c24f230f263820
Add MathText drawing functionality to Context2D classes.

Change-Id: I1168be82fb0a1f5d9a2a08c86801531945f867dc
Add vtkMathTextActor for rendering equation overlays.

Change-Id: I02b4376726ba87d2d6bedffc9ac67d56d5066c34
Add vtkMathTextActor3D for rendering equations in 3D space.

Change-Id: If11d17e914b1af5607237f7c6e8b08bd97aee29b
Bump included gl2ps sources to v1.3.6.

Includes a modification to the gl2psTextOpt function which
adds a color option.

Change-Id: I467b56dd870a3e87054b42125e373f0c0baad387
Add support for gl2psSpecial with PDF output to gl2ps.

Change-Id: I2229456ad3f254869d34009143b17eadcac8c7bf
Update vtkGL2PSExporter, add Rendering/GL2PS module

* Fixed bitmap rasterization.
* Added ability to exclude specific 3D props from the rasterization
  process, if enabled.
* Improved support for text rendering.
* Added method to vtkRenderWindow to collect all visible
  vtkActor2D objects that are vtk[Math]TextActors or use a
  vtkTextMapper.
* Add support for Context2D drawings
* Add CMake/CompareFileMD5.cmake script to compare postscript files
* Remove old GL2PSExporter python test
* Modify gl2ps sources to disable writing timestamps (prevents
  useful MD5 hashing for regression tests)
* A static string is used as the image title by default.
* Add vtkGL2PSUtilities, a collection of static functions that
  interact with GL2PS to render vtk objects.
* Add a gl2psGetFileFormat() function to the bundled gl2ps library.

Change-Id: Ia6fafc8e4d0a49bd9fdbecf32f43925a0aab7050
Add a vtkMatplotlib module.

* Isolates python dependency away from MathText
* Adds tests for MathText functionality.

Change-Id: Ib0f87248e7f73ead5d1904b72e7053537907bfd1
Add a GL2PS special case for vtkTextActor3D.

This implements a vtkFreeTypeTools::StringToPath method that
generates path data describing the outline of a rendered text
string. This path gets transformed to match the vtkTextActor3D's
appearance, then projected into 2D and drawn to the GL2PS buffer.

Change-Id: I2513a9d03799f290688624dd09f419def03e2996
Add functions to check if MathText is available at runtime.

bool vtkContext2D::MathTextIsSupported()
bool vtkContextDevice2D::MathTextIsSupported()
bool vtkMathTextActor::IsSupported()
bool vtkMathTextActor3D::IsSupported()

Availablity of MathText can also be check from anywhere using
vtkMathTextUtilities::GetInstance() != NULL.

Change-Id: I288bc94ddfdda578edb2f4618035de68db3c583f
Add missing return statements to tests.

Change-Id: I2890e67e383f8af88a9175e4497c5167c6d22468
Clean up some compiler warnings on Mac and Windows.

Missing cases for switch on enum, unused parameters.

Change-Id: I4ea2ae779e0f8ab0b4b9a3220798113ae1d98c42
Merge 'VTK/master' into MathTextGL2PS

Resolved Conflicts:
	Rendering/MathText/vtkMathTextUtilities.cxx
          * Header changes clashed

Change-Id: I3513fe9e07af2f6c161a8222f02badebee3feda1
Merge topic 'MathTextGL2PS' into master

90090e99 Merge 'VTK/master' into MathTextGL2PS
32b956e8 Clean up some compiler warnings on Mac and Windows.
8a1a5278 Add missing return statements to tests.
b7c0d1cc Add functions to check if MathText is available at runtime.
564112e2 Add a GL2PS special case for vtkTextActor3D.
c2f54b97 Add a vtkMatplotlib module.
82e58fc1 Update vtkGL2PSExporter, add Rendering/GL2PS module
e74980cc Add support for gl2psSpecial with PDF output to gl2ps.
6fc42bb5 Bump included gl2ps sources to v1.3.6.
cbecf3d6 Add vtkMathTextActor3D for rendering equations in 3D space.
a7a7c25a Add vtkMathTextActor for rendering equation overlays.
f16724a2 Add MathText drawing functionality to Context2D classes.
a50a557c Add API to generate vtkPath data and colored images from MathText.
b8a3c859 Add a vtkPath class to represent lines and Bezier curves.