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
Support for getClassName() from Android API level 18.
Merge pull request #1334 from paymand/android_getClassName

Support for getClassName() from Android API level 18.
Allow .ipa extension for desired capabilities param 'app'
Merge pull request #1336 from ecomrobotics/ios-allow-use-ipa-in-app-param

Allow .ipa extension for desired capabilities param 'app'
move android controller methods into their own file
we don't use webatoms for android now that we use chrome
initial work on refactoring adb
finish migrating install logic
migrate port forward logic
migrate push unlock and push appium
extract uiautomator behavior into its own object/library
run commands from uiautomator.js, and migrate activity waiting methods