docs: added info about install nginx.
misc/lxc: added nginx installation.
removing logic from remove service instance handler.
service: improved service instance tests.
Merge branch 'master' of github.com:globocom/tsuru
service: removing service instances by name.
service: removed unused attribute from tests.
cmd/logs: improved usage.
api: unexport login handler
service: make bind test more reliable

Avoid "Test killed: ran too long" failures, as reported in
https://travis-ci.org/globocom/tsuru/builds/5968318.
docs/overview: fixing more typos and improving some phrases.
docs/overview: added two more sections drags
auth: handling with error return byt newToken.
etc: added a value for hash-cost in sample configs.
cmd: fixed the jsonWriter.

using a buffer to get the response data.

Related to #374.
go vet.
cmd/log: fixed tests.
cmd/log: testing json writer buffer.

Closes #374.
cmd/log: fixed `tsuru log -f -l`.
fixed log test.