Separate the localScheme and hdfsScheme from FileSource.

This will enable the reuse of the *Scheme traits with a new subclass of SchemedSource that is not a FileSource.
Add a TemplateSource class.

This provides access to the cascading TemplateTaps through a scalding Source object. Follows the pattern of FileSource.
Adds tests for the new TemplateSource.
Cleanup documentation and imports.
Add `filterNot`
It's common enough to have it as convenience method I think.
It's also one of the typical scala collections methods, so having
it around is nice for people coming Scala expecting it to be there
"just like in scala".
use _ syntax for fn
style fix
added `filterNot` to `TypedPipe`
incl. test for both filters
[formatting] empty line between classes
Merge pull request #729 from ktoso/filterNot

Add `filterNot` to RichPipe
Extract createLocalTap from FileSource.

Fixes compile errors in scalding-commons.
Merge pull request #726 from lewchuk/develop

Enable use of Cascading TemplateTaps in scalding.