chore: remove intellij project files (#2042)

The .idea files have drifted and no longer help to establish a useful
project in Android Studio. Delete them.

Delete the .travis.yml which is not being used, and delete a stray .iml
file that was commited to the -core module.

Author: jamesonwilliams

.gitignore

@@ -36,15 +36,7 @@ captures/
 
 # IntelliJ
 *.iml
-.idea/workspace.xml
-.idea/tasks.xml
-.idea/gradle.xml
-.idea/assetWizardSettings.xml
-.idea/dictionaries
-.idea/libraries
-.idea/caches
-.idea/codeStyles
-.idea/misc.xml
+.idea
 
 # Keystore files
 # Uncomment the following line if you do not want to check your keystore files in.