#34 : Fix Ctrl + click not opening a new tab

Don't load url if user hold Ctrl or Cmd when he click (default behaviour
so)
Update README.md
Merge pull request #36 from LuminusDev/fixCtrlKey

#34 : Fix Ctrl + click not opening a new tab
Bug: Firefox crash if caching disabled

If pageCacheSize is set to 0, Firefox chokes when looking up into the undefined `cache` object.
Also cleaned up debugging message that would fail if cache lookup failed.
Merge pull request #39 from jbellsey/master

Bug: Firefox crash if caching disabled
Add linting rules