python assets builder
Pipelined assets building system.
Builders operations:
builder1 & builder2
produces new builder with input == concatenated builder1 and builder2 outputsbuilder1 ^ builder2
executes builder1, forgets it's output and return builder2builder1 | builder2
sets builder2 input == builder1 outputbuilder1 > 'somefilename.ext'
writes builder1 output to 'somefilename.ext' and returns builder1