Bump master to 3.19 alpha

Signed-off-by: tobiasKaminsky <tobias@kaminsky.me>

build.gradle

@@ -87,7 +87,7 @@ repositories {
 
 // semantic versioning for version code
 def versionMajor = 3
-def versionMinor = 18
+def versionMinor = 19
 def versionPatch = 0
 def versionBuild = 0 // 0-50=Alpha / 51-98=RC / 90-99=stable