Allow configurable version numbers for built binaries.

Through gradle system properties (-P), able to configure:
* MAVEN_UPLOAD_VERSION = binary versions [Default Value: 1.0.0-beta3rc1]
* MAVEN_BUILD_LOCAL = if true, deploys artifacts to local repository.
otherwise, deploys binary to MAVEN_REMOTE_REPO_URL [Default Value: true]
* MAVEN_REMOTE_REPO_URL = maven remote repo url (e.g.
file://c:/some/directory or http://artifactory.com) [Default Value:
http://thaliartifactory.cloudapp.net/artifactory]
* MAVEN_UPLOAD_USERNAME, MAVEN_UPLOAD_PASSWORD = credentials for
MAVEN_REMOTE_REPO_URL [Default Value: user/[*]]

System and project properties are propogated to subsequent child gradle
tasks.
Set default value for MAVEN_BUILD_LOCAL
Remove usesSdk from Android manifest.

These values will be replaced by Gradle. Removing the properties from the
android manifest to avoid confusion.
Simplify

Remove the LOCAL_BUILD flag and just use the REPO_URL straight up. Removed
the default values as these should be set in your properties file. If not,
it'll fail the build.
Merge pull request #64 from jpoon/master

 Allow configurable version numbers for built binaries.