Added marking schemes
Added Student Submissions 
Added marking (only one right answer atm, marking is all or nothing aswell, this can be edited once it's been tested more)

Marking only works if student submission is created with each section/subsection/answer being added IN ORDER of the actual paper, I will change this soon by adding an ID to each that they can be sorted by.

TODO: ADD XML saving to marking scheme and student submissions
Merge branch 'master' of https://github.com/apic6/MELT.git