Add failing test based on reproduce in #35.

Evict unavailable elements and windows to prevent COM exceptions and to
free memory. See #35. The COM exceptions from a growing set of
unavailable elements may be the cause of degrading performance as well.

Use the RuntimeId property to speed up equality comparison for known
elements and windows. Along with this, catch possible COM exceptions
during equality comparison if the element is no longer available.

Closes #35.

Evict unavailable elements

The spec is unclear on when input sources should be added to the input source map. Previously it was being done in `ExtractActionSequence` but the problem with doing it there is that there's no way to know if `GetOrCreateInputSource` is returning an existing input source or creating a new one, causing #43.

Move the logic to add an input source to `GetOrCreateInputSource` to fix  this.

(It would kinda make sense to do it instead in `CreateInputSource` but the spec defines a caller of this method which adds the input source manually :/ )

Fixes #43

Add input sources in GetOrCreateInputSource

Prevent stale enumerators and concurrency issues while adding or
victing unavailable elements or windows. Closes #42.

Thread safe evicting of elements

Use very specific error messages to indicate capability mismatches.

Better capability matching errors

Along with this, use the new timeout capability properties. Fixed an issue that the timeouts could be floating point numbers.

Add Windows-specific extensions similar to appium-windows-driver to allow easier replacement.

Add a specific hover test and rename the other tests according to the test naming convention.

Update dependencies

Basic windows extensions