make tox not run functional tests or coverage by default

[robdennis]

as outlined in #44 the current tox invocation can take (as of 4/1/2014) upwards of 7.5 minutes.

this comment describes some initial thoughts on remediation: https://github.com/appliedsec/sideboard/issues/44#issuecomment-39205243

and this ticket is doing all but the first one