Provides some functions for working with Young diagrams.

- partitionsequence: computes partition sequence for an integer partition
- a \ b creates the skew diagram for partitions (tuples) a, b
- isrimhook: checks if skew diagram is a rim hook
- leglength: computes leg length of rim hook
- character: computes character of irrep of Sn
Merge pull request #6 from jiahao/young

Provides some functions for working with Young diagrams.