Fix writing of curriculum metrics to CSV

[will-hou]

Resolves #8

Also matches the formatting of the metrics file exported by curricular analytics more closely:

• Complexity displayed to one decimal place
• Delay factor displayed to one decimal place
• Course credit hours displayed as a whole integer

[will-hou]

Testing with the public VCU Public Computer Engineering curriculum

Left is file with metrics downloaded from Curricular Analytics. Right is file without metrics downloaded from Curricular analytics and processed with CurricularAnalytics.py

Only differences are the ordering of pre-reqs but I don't believe that is important (also out of scope for this PR)

[SheepTester]

I'm not sure if we should match Curricular Analytics exactly since unit counts at some universities aren't necessarily an integer. For example, UCSD's language classes are 2.5 units

[will-hou]

I'm not sure if we should match Curricular Analytics exactly since unit counts at some universities aren't necessarily an integer. For example, UCSD's language classes are 2.5 units

Ah didn't know that. I removed that change

[will-hou]

@SheepTester Are there any other items you want me to address before this can get merged? Thanks!