fix - operator + unit tests #34

Fix case when calculating sub on rational and complex
Fix error messages for invalid numbers in complex op

CHANGELOG.md

@@ -31,6 +31,7 @@
 * fix option -t --trace in Node REPL
 * fix `eqv?` on exact and inexact numbers according to R7RS spec
 * fix `exact->inexact` on complex numbers
+* fix - operator
 
 ## 1.0.0-beta.11
 ### Breaking

README.md

@@ -2,8 +2,8 @@
 
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