Fixed language parameter.
Added simplified CourseSpiderNew. Uses Item Loaders.
Skipped failing evaluation tests.
Course repository using SQLite.
Updated repository to accept Items.
Fixed SQLAlchemy repository queries.
Added unicode test.
Fixed ECTS parsing. Fixed unicode insert problem.
Added pipeline to store courses in DB.
Split prereqs and prereq desc. Simple prereq processor (to be improved).
Added pydot module to plot graphs from prereq strings.
Renamed pydot to viz. Added OO version of shunting yard.
Fixed operator precedences.
Renamed operator nodes.
N-ary operator parsing instead of binary.
Fixed N-ary argument parsing.
Moved graph generation to course.
Fixed course prereq columns mapping.
Renamed AstWalker module.
Renamed method.