Add PayPal Touch app-switch support
Update podspec version
Drop-in UI support - bring-forward of reference

Brought forward the drop-in UI known issue. Would not want someone who really wanted to PayPal Touch to have to scroll all the way to the end to notice that it won't yet work with drop-in.
Minor edit
sdk gBblblLs - Re-enable user interaction before app switch

* Fix missing `willAppSwitch...` delegate calls, and rename for brevity
* Add BTPayPalAppSwitchHandlerSpec
Add button param to payPalButtonDidCancel: delegate method
Dismiss view controller in drop-in "returning" case on app switch success

Also implement the payPalButtonDidCancel: delegate
method, and add some comments better explaining the
two cases.

https://trello.com/c/elYGiPk7
Merge pull request #50 from braintree/feature/elYGiPk7-fix-drop-in-repeat-app-switch-dismissal

Fx drop in repeat app switch dismissal
Add CHANGELOG entry for 3.2.0-rc2, update PayPal Touch README
Bump pod version to 3.2.0-rc2
sdk oU86WRAA Respect disableTouch flag for PayPal app switch
sdk oU86WRAA rename btPayPal_disableAppSwitch to btPayPal_isTouchDisabled
sdk oU86WRAA Adding btPayPal_isTouchDisabled on BTClient+BTPayPal and calling it instead of BTClientToken from BTClient.
sdk oU86WRAA Remove fetchPaymentOptionsForScheme from BTClient
sdk DyV5X9sE - Refactor BTHTTPUtils to expose query string methods
Update the changelog for rc3
Bump pod version to 3.2.0-rc3
sdk oU86WRAA - Remove unused BTPaymentApp class
Add first version of Venmo Touch
Change merchant ID key from braintreeMerchantID to braintree_merchant_id