Changes how xcpretty is pipped to xcodebuild.
Fixes issue with Podfile.
Updates Cocoapods to 0.35.0
Renames shared scheme to WLXBluetoothDeviceShared #2.

This is hack to avoid an issue in Cocoapods when running
tests from the command line.

https://github.com/CocoaPods/CocoaPods/issues/2929
Adds xctool to rake tasks.

Renames XCodeBuild to XBuild. Now it can use xcodebuild or
xctool to build the project.
Updates travis.yml to download the lastest version of xctool. #2