PayPal SDK Integration

- Adds paypal SDK libs
- Adds PayPal credentials to manifest
- Adds PayPal environment setting ("sandbox")
- Adds Camera Permissions for PayPal card scanning
- Adds Camera features for PayPal card scanning
- Defines services and activites for PayPal and CardIO
- Adds PendingPaymentActivity and tests PayPal integration
- Updates the Request class to expose its bid value in PayPal-friendly getters
- Updates Helpers to add a vendor in the mock Request
Merge pull request #67 from steffanc/paypal

PayPal SDK Integration
Add VendorWait activity screen.

Still need to actually show the vendors nearby.

Handle the intent between hitting the 'X' mark and going back to the previous Activity.  In the process,
we cancel the intent.

Create a bundles directory for all the Intent bundle data we pass back.  Intents contain Bundles of data, so
I figure it's better to call it this name.
The extra title() is redundant.  Clicking on it just shows the person's name again.
Create a Parse callback handler for rendering markers for a given Google Map and icon color.

More updates to vendor wait.

Remove redundant Request declaration.

Add interface for onError() exceptions and use an IconGenerator provided.

Add You icon.

Implement a more generic ParseResultCallback interface.

Implement ParseCallback interface.