1 IContextAware interface.

Appium project needs this. If the similar interface exists at
selenium-java so why it can't be at C#/.Net client. :)

2 PageFactory enhancement.
These tools were implemented the perfectly similar way as it was done in Selenium Java. Now it is possible to design your own attributes/algorithms in order to decorate fields/properties by:

IFieldDecorator
ILocatorFactory
IElementLocator

Default implementations are already here. They can be extended, their virtual methods can be overridden

Some more about

2 PageFactory enhancement.

Appuim project needs this in order to provide the following use case (field of page/screen object):

[FindsBy(How = How.CssSelector, Using = "relevant css")] //if there the similar browser UI as UI of a //native app
[AndroidFindBy(UIAutomator = "ui Automator locator for Android")] //if page object is going to be used against Android
[iOSFindBy(Accessibility = "accessibility for iOS")] //if page object is going to be used against 
//iOS
IWebElement targetElement;  //element is used for the mobile and browser testing

It is already present on the java-client side. If it is interesting details are below:
appium/java-client#68
appium/java-client#126
appium/java-client#140
appium/java-client#145

I dropped into the #selenium IRC channel on freenode and mentioned this PR. Here's a quick response:

[11:23] <jimevans> nope. i'm not merging that.
[11:23] <jimevans> it should be two pull requests, not one.
[11:24] <jimevans> and i'm not taking a dependency on another third-party library that can't be ilmerged into a single assembly.
[11:24] <jimevans> which castle.core can't.
[11:30] <jimevans> if the author wants to break it up into two pull requests, i'll look at them.

So breaking this into separate pull requests will make things easier to review.

Ok! I'll separate it soon.

Actually there is no Castle.Core reference anymore.

I am closing this PR as it should be divided...

Was splitted to:
#305
#306