SCC fine decomposition
SCC seems to work
image-writing functions
introducing spasm_partition + actually testing SCC
Added Connected Components test + fixed bugs
cosmetic bug fixes
more tests, less bugs in CC
CC puts rows and cols in the natural order inside each block
debuting DM again
Fix several bugs in CC, DM
Fixed copy-paste bug
Fixed partition initialisation bug
Utility functions
bug fix in image output
Change order of arguments in matching (row first !).

This commits breaks things
connected components take an optional matching and respect it
move matching computation outside of DM (this allows the re-use of the transpose of A)
SCC also fills the column permutation
added a DM test
trying stuff