remove .request accept tests the fail

due to
https://github.com/expressjs/accepts/commit/5975ce464575bd0fddfdd3d41796
958cd6bfc20b. passing nothing into accepts() is silly anyways.
bump should just because
set-type -> mime-types

removes mime dependencies from the dep tree.
liberally sets charset because some express users complained about bad
browsers using the default charset.
0.6.2
assert non-error obj pass to app.onerror, fixed #287
remove response.append(), use vary module
context: delegate etag/last-modified
Merge pull request #288 from dead-horse/issue287

asset non-error obj in app.onerror, fixed #287
remove if (!err) from app.onerror

we assert instanceof Error right below
fix res.type= for unknown types

because we changed from mime to mime-types. ideally, we should just not
set the content-type, but this way it’s backwards compatible. we can
change it later.
update finished
0.6.3
Merge pull request #291 from koajs/vary

remove response.append(), use vary module
Merge pull request #292 from koajs/context-delegate

context: delegate etag/last-modified
docs: discuss custom properties

related to #292. might be placed better somewhere else
delegate: remove this.append()
0.7.0
remove .status=string #298
remove res.statusString
Merge pull request #299 from tmilewski/remove-status-as-string

remove .status=string