- if csvstack files have headers, union the headers and align data
 - remove stray print
 - handle first file coming into cvstack from stdin
 - tests for aligning csvstack
 - update docs for csvstack
 - examples for csvstack aligning code
 - more robust testing for stdin and csvstack, some bugs squashed
 - simplify condition of writing stdin_firstrow
 - chore: Tidy and comment csvstack code