Basic implementation of sending If-Modified-Since per request.
IfModifiedSince: this patch passes all existing tests.
Merge branch 'master' into IfModifiedSince
IfModifiedSince: Added ability to recover the requested headers in MockRemoteServer.
IfModifiedSince test case written and passing.
IfModifiedSince: improve comments.
Handle MockRemoteServer.Headers errors correctly in IfModifiedSince
branch.
Merge branch 'master' into IfModifiedSince

Conflicts:
	test/fetcher_test.go
cassandra: added more config items for gocql

The main item I needed was DiscoverHosts, as in production use all
connections being used were for a single machine at a time.

Also, console/model.go was not using cassandra.GetConfig to get a
cassandra config, so it was not using the upped default timeout, thus
the console was more likely to hit timeouts. Now they share, though soon
I'll be doing work to share more stuff.
Merge pull request #78 from iParadigms/IfModifiedSince

If modified since
Merge pull request #83 from iParadigms/add-gocql-config

cassandra: added more config items for gocql
Merge branch 'master' into NormalizeUrl