#64 Android support and custom sources [Kotlin/dok...

# dokka

[user]

#64 Android support and custom sources
[Kotlin/dokka] Pull request submitted by porokoro
This adds an initial support for Android library projects.

Also you are able to set the source directories directly from the Gradle plugin now, for the case that you have a special configuration or you have plugins that specify the sources in another way.

I separated the Android support in its own plugin so that users which have a plain Kotlin library don't need to pull the Android dependencies, which they don't need obviously.

Fixes #61.

Please note: I modified the project in Gradle only (build system wise) and didn't change anything in the IntelliJ IDEA configuration. In my opinion the whole .idea folder should be removed because the configuration gets overridden every time you sync with Gradle anyway.
But I have seen there are some special configs for generating Kotlin's docs and if you tell me what needs to be changed in the IntelliJ config I will change it accordingly.