detectcycles: A source code dependency cycle checker

[Mario Kröplin]

I did not mention it in the README, but the tred filter used in 
https://code.dlang.org/packages/depend complains about cyclic 
dependencies.

I am currently working on a branch, where the transitive 
reduction and the corresponding warnings are built in.

While this tool is for D only, it also allows to visualize and to 
check dependencies.