Remove core tests from coverage

Author: Lee Miller

tox.ini

@@ -11,7 +11,7 @@ setenv =
 deps = -rrequirements.txt
 commands =
     python checkdeps.py
-    coverage run -a src/bitmessagemain.py -t
+    python src/bitmessagemain.py -t
     coverage run -a -m tests
 
 [testenv:lint-basic]