Add coverage and coveralls

Author: kennknowles

Diff for: .coveragerc

@@ -0,0 +1,3 @@
+[run]
+branch = True
+source = jsonpath_rw

Diff for: .gitignore

@@ -9,3 +9,5 @@
 /README.txt
 /dist
 /*.egg-info
+
+.coverage

Diff for: .travis.yml

@@ -7,4 +7,7 @@ python:
 install: 
  - "pip install . --use-mirrors"
  - "pip install pytest --use-mirrors"
-script: py.test
+ - "pip install coverage coveralls"
+script: coverage run setup.py test
+after_success:
+ - coveralls