Bugfixes

I ran into an issue when trying to use includes, where I wasn't able to reference something from one of them in the main file. Some digging revealed that the processIncludes function was actually adding to the end of the main array. I changed that functionality so that it would prepend to it instead (it actually appends the main one to the one with the includes and uses that).
There was also an issue with nested placeholders. For example, if I wanted to do:
```
<customProvider(<current()>)>
```
I would get an error. The idea for the functionality was there though. So I changed the regex to match nested placeholders better, and added a loop to go through all of them.
I also included a few phpdoc fixes here and there.
Not sure if this repo follows PSR-2, but i dont think this matches PSR-2