replace i-figured with hallon for figure numbering per chapter and sub-figures

[JeyRunner]

fixes #27

[mohe2015]

I will look into this a bit. There is no previous work yet right?

[mohe2015]

@JeyRunner Is it correct that we need to support chapter based equation numbering but hallon does not support this yet?

[JeyRunner]

@mohe2015 I did a simple test some time ago for using hallon (just added it externally and not inside the template). But for the very large example document I had, it caused "layout did not converge" issues when setting up per-chapter figure numbering, but I did not investigate this further.
Feel free to make a PR for changing to hallon. Chapter-based equation numbering is a current feature of the template, but I am not sure if it is used. Maybe only for the equation numbering i-figured (or some other package) can be used and hallon for figures.