Fixed bootstrap build error to download dependencies

Below is error message. 

[ERROR] Failed to execute goal on project bootstrap: Could not resolve dependencies for project io.appium.android:bootstrap:jar:1.0.0-SNAPSHOT: The following artifacts could not be resolved: android:android:jar:4.3_r1, android.test.uiautomator:uiautomator:jar:4.3_r1: Could not find artifact android:android:jar:4.3_r1 in central (http://repo1.maven.org/maven2) -> [Help 1]
Merge pull request #1321 from samaitra/master

Fixed bootstrap build error to download dependencies
Ensure APK is signed
Merge pull request #1323 from bootstraponline/master

Ensure APK is signed
no need for this to be a property
break apart ios into core and controller parts
pull out remote debugger related ios functionality into its own file
Merge pull request #1328 from jlipps/master

break ios.js up into logically related files