feat: initial commit of Railtrack Pro prototype with complete test suite

node_modules/exit-x/test/fixtures/10-stdout-stderr.txt

@@ -0,0 +1,20 @@
+stdout 0
+stderr 0
+stdout 1
+stdout 2
+stderr 1
+stdout 3
+stderr 2
+stderr 3
+stdout 4
+stderr 4
+stdout 5
+stderr 5
+stdout 6
+stderr 6
+stdout 7
+stderr 7
+stdout 8
+stderr 8
+stdout 9
+stderr 9