This an IItemRenderer port done properly and tested with additional builtin features. This makes it so you can have dynamic and open gl calls for items just like in 1.7.10. There are additional parameters. No code actually remains from elix_x's(a0.5+) IItemRenderer as of the beta builds as it's more like it use to be with further control.

Features:

Full Override for one specific item instead of multiple meta data calls and unnecessary storage
Full Override for gui overlayers like tooltips and green tool bar but, you have to override it as it's default inside of the interface
Fast Render options builtin for your renderer to implement
Access to Camera Transformations
Access to the full ItemStack including NBT data
Access to partial ticks
Access to Entity Holder Data that is currently rendering your IItemRenderer instance
Ability to render IBakedModels when and if you specify with and without enchantments
Mipmap handling automatically
enchantment rendering

ToDo:

Fix Github bugs
1.1 Add IBlockRenderer where you don't need a TE for your block to render it
Resource Pack 1.8+ support

Devs:
go to the source of silkspawners for examples of how to use but, it's pretty much the same as 1.7.10 with more options.

Why No TEISR If Item Isn't Yours:

no access to item stack or nbt
cannot register individual items only per meta data

Why No TEISR in General:

Partial ticks are always 1.0F instead of current mc's partial ticks
Cannot render other IBakedModels from other objects safely(without endless recursion happening)
The Tile Entity Rendering in the parameter is always null when not in block form
No access to camera transformation types
Highly encourages users to have the same exact render code from the TE to the item form or other camera tranformation types there goes your if statements.
No access to entity holder data that is currently rendering your item such as entity item, player, zombie or item frames etc...

IItem Renderer Reborn