* Add `make ideploy` command for publishing iOS releases.
* Get release version from latest ios git tag.
* Use caffeinate to prevent the system from sleeping during the deploy process.
* Checkout tag to ensure correct commit is used
* Fail if release has already been published (not a draft) on GitHub
* Add publish step logging and colorize it.
* Allow s3 upload to show progress.
* Use build/ios/deploy directory for downloaded release zips; always overwrite via -O flag.
* Add zip filename to s3 step.
* Auto-install github-release command
make iproj now produces a target that pulls together static libraries like core and platform-ios into a real dynamic framework. iosapp is pretty much just a regular iOS application that links Mapbox.framework (except for the inclusion of default_styles.hpp). iosapp runs fine in the Simulator and on a device, and the same is true for any application linking against Mapbox.framework.
The ipackage target produces both a Bitcode-disabled static framework and a Bitcode-enabled dynamic framework, eliminating the need for a separate framework.sh. It disables code signing, since that happens on copy when the framework is embedded inside the application bundle. It also merges the device and simulator builds into a single fat framework.
Also bumped itest minimum deployment target to iOS 8.0, the first version that supports linking frameworks.
Fixes#828.
