Removed unused var verticesCount from OBJMTLLoader.js

Removed `var verticesCount` as per #4968.
Add the file name before the code in Three.js
Also add the filename in the build.js build
Merge pull request #4971 from eyethereal/issue-4968

Removed unused var verticesCount from OBJMTLLoader.js
Object3D add() can take arbitrary arguments and is chainable.

Now is possible to do:

    obj.add( obj2, obj3 );

As well as:

    obj.add( obj2 ).add( obj3 );

Fixes #4958.
Throw a decent error on missing font.

It throws an error when the font is missing.
Ex: "The font helvetiker with normal weight and normal style is missing.

Fixes #4923.
Merge pull request #4981 from gero3/patch-22

Throw a decent error on missing font.
Change the way the extra info appears
Support spaces for tags that only ever contain a single text string value (i.e. material names, texture file names) in the OBJ converter.
Support OBJ and MTL files that may contain tags split onto multiple lines, using a trailing backslash to signify the split, in the OBJ converter.
Object3D remove() can take arbitrary arguments.

Now is possible to do:

    obj.remove( obj2, obj3 );

From discussion in #4958, see also #4977.
Merge pull request #4982 from manuq/fix4958b

Object3D remove() can take arbitrary arguments.
Merge pull request #4984 from okready/patch-2

Support OBJ and MTL files that may contain tags split onto multiple line...
Merge pull request #4975 from gero3/AddExtraInfoBuild

Add extra info build
Merge branch 'dev' into patch-1

Conflicts:
	utils/converters/obj/convert_obj_three.py
Merge pull request #4983 from okready/patch-1

Support spaces for tags that only ever contain a single text string valu...
Fixed incorrect vertexColors values.
Updated builds.
Fixed npm publish instructions
Merge pull request #4985 from rtsao/dev

Fixed npm publish instructions