Extrude Splines Example: Dispose of geometries properly

OBJExporter: log material names

Curve: Fixed docs

OBJLoader2 and WWOBJLoader2

Geometries: Added missing .mergeVertices() calls

Compute ParametricGeometry normals from tangent vectors

Add guard for IE11 and Edge that don't support lose_context extension.

Examples: Refactor webgl_geometry_extrude_splines

Update webgl_marchingcubes.html

Update link to avoid HTTP 404.

Adjusted to removal of MultiMaterial

OBJLoader2:
- Removed underscores from functions of private classes

WWOBJLoader2:
- Adjusted naming of web worker classes

Improvements since initial external V1.0.0 release:
OBJLoader2:
- Removed need for making Parser public. OBJLoader2 has a build function for web worker code.
- MeshCreator is now private to OBJLoader2

WWOBJLoader2:
- Added checks for Blob and URL.createObjectURL
- Worker code build: Removed need to adjust constructor and some new Object calls
- Allow to properly set CORS to MTLLoader via WWOBJLoader2 and WWOBJLoader2Director
- Now allows to enable/disable mesh streaming

Example webgl_loader_obj
- Added GridHelper
- resources to load are now defined outside example classes

Example webgl_loader_obj2_ww
- Allow to clear all meshes in
- Allows to load user OBJ/MTL files
- Added GridHelper
- resources to load are now defined outside example classes

All Examples:
- Created one page examples and tuned naming
- All examples now use dat.gui
- Removed namespace "THREE.examples"
- Fixed comment typos
- Fixed some code formatting issues
- Fixed tabs in examples

General:
- Headers now carry references to development repository

Curve: Refactoring

VTK header is now parsed and used to extract all the compressed data

Editor: Fixed #10574

docs/index.html: Prevent the browser from flooding the DOM with empty tags