Issue 80: adjusted math course to working edx courses

[oliverlkelly]

iss80 on Forrest Knight repo regarding broken links for MIT courses is repaired with this commit. All content adjusted and broke/irrelevant content removed/corrected.

also added the LSE pre-calculus course to the new courses as it is more directly tied to this new set of courses. Maintained ASU course in other section

[DeeptangshuSaha]

I think I found the original courses supposed to be there Calculus 1A: https://openlearninglibrary.mit.edu/courses/course-v1:MITx+18.01.1x+2T2019/course/ Calculus 1B: https://openlearninglibrary.mit.edu/courses/course-v1:MITx+18.01.2x+3T2019/course/ Calculus 1C: https://openlearninglibrary.mit.edu/courses/course-v1:MITx+18.01.3x+1T2020/course/