Normalise ignore files

- Consistent order and contents (where possible)
- Prepend .gitignore paths with slashes where appropriate

Signed-off-by: Aanand Prasad <aanand.prasad@gmail.com>

.dockerignore

@@ -1,5 +1,10 @@
+*.egg-info
+.coverage
 .git
+.tox
 build
-dist
-venv
 coverage-html
+dist
+docker-compose.spec
+docs/_site
+venv

.gitignore

@@ -1,9 +1,10 @@
 *.egg-info
 *.pyc
-.tox
+/.coverage
+/.tox
 /build
+/coverage-html
 /dist
+/docker-compose.spec
 /docs/_site
 /venv
-docker-compose.spec
-coverage-html