Collect test coverage results for collectors too

[shortdudey123]

No description provided.

[coveralls]

Coverage remained the same at 24.964% when pulling 58a0047 on expand_coverage_settings into 1c0935b on master.

[shortdudey123]

Looks like each collector also needs __init__.py to be considered by coverage

Only importable files (ones at the root of the tree, or in directories with a __init__.py file) will be considered. ~ http://coverage.readthedocs.io/en/coverage-4.3.4/source.html#execution

$ find src -name __init__.py
src/diamond/__init__.py
src/diamond/handler/__init__.py
src/diamond/utils/__init__.py
$