Update nuget packages to latest

Signed-off-by: Adam Warner <me@adamwarner.co.uk>

Merge pull request #31 from PromoFaux/stringsplitter-exceptions

Throw exceptions when invalid params passed to StringSplitter

remove no longer required line from README

Signed-off-by: Adam Warner <me@adamwarner.co.uk>

Merge pull request #23 from PromoFaux/development

1.4.1 release

Merge pull request #14 from PromoFaux/development

V1.4 release

Merge branch 'master' of github.com:PromoFaux/Matterhook.NET.Matterho…

…okClient

Merge pull request #7 from PromoFaux/fix/BrokePosting

Maybe one day I'll write tests.

Merge pull request #6 from PromoFaux/new/betterMessageSplitting

Vastly improved message splitting logic. Will preserve words between …

Merge pull request #5 from PromoFaux/tweak/messageLength

Add optional parameter for message length

Adjustments to appveyor yaml to tidy up version number on nuget package