Remove the rest of internal module coupling between packages

fixed extends doc issue

give a method for plugins to add custom middleware

add .fnt as an xml loader extension

typo in comment

fixes #1709 outdated loader docs

whitespace

expose async and Resource

Remove pixi-spine dependency. Tested on real project :)

less ducktyping, use is* from loader; fixes #1628

Merge remote-tracking branch 'origin/dev' into dev

use pixi-spine plugin

move premade loader to main export

fix some bugs in the loader

Move items into their namespace ...

This commit also:

 - fixes some dangling whitespace,
 - fixes some incorrect docs in extras/mesh,
 - moves Text to core
 - moves BitmapText to extras
 - moves math constants to const.js

fix loading of bitmap font

get relative bitmap font loading properly.

better detection of bitmap font; should be relative to xml url now

loader already passes baseUrl, don't need to do it in add

export a premade loader

More docs again !

Docs fixes, improved the consistency of the deprecation, thanks @englercj ...

Also added a comment on the bitmap font parser, will leave the change
until we find a new caching system

fixed typo in cacheAsBitmap, fixed bitmap text and restored the font cache so we can debug it

Merge branch 'alvin/dev' into dev ...

Conflicts:
	src/interaction/interactiveTarget.js

Docs, spine and tiling sprite fixes, another deprecation warning

fix logic error in bitmapFontParser check:

massive jsdoc fixes

fixed typo in loaders/index.js; gulp build wasn't working because of this

some code linting.. ...

nice and tidy!

removed sneaky console.log