Minor fixes

[majdisorder]

• Updated .gitignore to latest from https://github.com/github/gitignore/blob/master/VisualStudio.gitignore
• Fixed inconsistent access modifiers for ExtendedClientConfiguration properties. All properties now have private setters, as I feel the configuratiuon object should be immutable.
• Changed MessageSizeThreshold type from int to long. This makes more sense, as IsLarge compares this with LongCount of the message bytes.
• Fixed ExtendedClientConfiguration ctor to copy the S3KeyProvider from 'other'.
• Fixed a typo in an exception message.
• Fixed typo in S3KeyProvider property and Interface name. I realize this could cause some issues concerning backwards compatibility, so maybe this deserves a major version bump.

[majdisorder]

just realized i forgot to change the type for the messageSizeThreshold parameter in WithMessageSizeThreshold

[raol]

Hm. I don't get why such a change was introduced.

[raol]

Please rearrange using as the were.
System* ones should come first.

[majdisorder]

I think it's resharper that orders the imports alphabetically on save. I'll see if I can disable this.

[raol]

And the build, it's broken
https://ci.appveyor.com/project/raol/amazon-sqs-net-extended-client-lib/builds/29319522

[majdisorder]

And the build, it's broken
https://ci.appveyor.com/project/raol/amazon-sqs-net-extended-client-lib/builds/29319522
m
hmm.. yes, I signed assembly so I could use it in my own project. Should not have committed that i guess. I'll revert and create a separate branch for this.