Optimize the algorithm to generate possible weekly schedules

[Yivan000]

The current implementation of the schedule algorithm is extremely slow. It needs optimizing.

as of 0.0.1:

No. of subjects	Time taken
2 subject	~500 ms
3 subjects	~500000 ms
4 subjects	~2000000 ms

[Yivan000]

I have devised a new algorithm in this commit:
dcf8db5

The new algorithm is far superior than the previous one, since it uses bitwise operators to check for conflicts.

as of 0.1.0:

No. of subjects	Time taken
2	~0 ms
3	~15 ms
4	~100 ms
5	~25000 ms
6	~600000 ms
10	3+ hours

[Yivan000]

Closing this as fixed for now as of 0.1.0. For new ideas as to generating schedules more efficiently, please comment them below.

[Yivan000]

Reopening due to slow initialization.