Updated and added PathCulture convention

The convention will now strip the culture from the URL, if it
was a valid culture, before passing it along for route matching
Added configuration object to fix #832 and fix #902

Configuration object allows enabling/disabling the localhost
rewrite and also to specify a callback for unhandled
exceptions
Merge pull request #903 from grumpydev/SelfhostUpdates

Added configuration object to fix #832 and fix #902
Merge pull request #898 from thecodejunkie/pathcultureurlrewriting

Updated and added PathCulture convention
Attempt to fix the CI build
Fixed #908

Accept header now always set if we go through negotiation. Initially
considered only setting it if the negotiator could match more than
one type (either by having a wildcard or multiple entries), but there's
still a chance that a processor may match in some weird and wonderful
way behind the scenes so seems sensible to always add it if we have
negotiated the response.
Merge pull request #910 from grumpydev/AcceptHeaderFix

Fixed #908
Fix for #911
Merge pull request #912 from grumpydev/BlankPathFix

Fix for #911
Fixed error message of Single-Assertion.
New testing assertions for HTML attributes.
Updated CsQuery
Fixed casing in nuspec file
Fixed the build

Top tip: when up update the version of a reference in project X,
also make sure you update the version in X.Tests too ;-)
Updated nuspec to force CsQuery update
Updated git ignore
Updated SSVE to support IfNull and IfNotNull
Updated assembly scanning logic

Moved loading of nancy assemblies to "Initialise" in the bootstrapper,
rather than in the ctor, and set the ignored assemblies on the
ADATS in the same place. Initialise is called before any container
resolution or anything else happens, so now the ignore assemblies should
be set before anything needs the scanner.

Also move the logic to only include assemblies that reference nancy assemblies
from the resource based text resource to the resource assembly provider
so all resource based providers can use the same filtered list.

Fixes #504
Closes #638
Fixes #418
Revved version
Updated SharedAssemblyInfo to v0.15.3