WIP: Generate API docs

[dsyme]

This is WIP related to #223 - it hosts the docs in the "master" branch and builds them out into gh-pages.

Submitting mainly to see if the doc generation works on Mono using Travis

[tpetricek]

This is currently failing because of how F# Formatting is referenced. Please change generate.fsx to use the recommended method from ProjectScaffold:

#load "../../packages/FSharp.Formatting/FSharp.Formatting.fsx"

You might also need to include code that explicitly sets the references on Mono (see this bit in ProjectScaffold).

Ping me or @matthid if it does not start working after the change!

[haf]

@tpetricek @matthid Ok, so I did that and now it's failing on the version of F# instead:

Compilation errors:
 - error: (0, 0) Assembly `fsi, Version=4.3.1.0, Culture=neutral, PublicKeyToken=f536804aa0eb945b' references `FSharp.Core, Version=4.3.1.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' which has a higher version number than imported assembly `FSharp.Core, Version=4.3.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'

[haf]

I'm closing this in favor of a PR that contains the aforementioned fix.