Add a FAQ section in Readme or Wiki

[thefzsalam]

List commonly encountered problems in a FAQ section in Readme or the Wiki. I would like to suggest the following:

• When importing a barebones gradle project, (for example:https://github.com/czak/minimal-android-project), if you encounter a classpath not found error, there might be some error in build.gradle. Try opening a command line and type: gradle build to see if there's any error. (for example, could not download the plugin)
• atom-ide-ui package is required for this package to work.
• If you encounter an error like this: The declared package does not match the expected package as described in this SO question, create a file named .classpath next to build.gradle and add the following:

<?xml version="1.0" encoding="UTF-8"?>
<classpath>
    <classpathentry kind="src" path="src/main/java"/>
</classpath>

• Note: Change path="src/main/java" to where your packages reside. (The SO question explains the issue clearly. It would be appreciated if someone could express the issue in concise words here to explain our problem clearly.)
• To enable completion for android sdk, add the following to the above mentioned .classpath file between <classpath> ... </classpath>: <classpathentry kind="lib" path="/path/to/android-sdk/platforms/android-XX/android.jar"/>
• Where XX stands for compileSdkVersion specified in build.gradle.

[damieng]

atom-ide-ui package is required for this package to work

Is already in the README.

Would accept a PR to add an FAQ around the project system though - that would be super helpful! :)

[CaptainBeyondDS8]

Should be noted according to the Eclipse language server readme that Gradle support is minimal and Android projects are not supported.

[damieng]

I think rather than try and keep up with the language servers README we should probably just link directly to it from our README when it comes to 'compatibility and features'?

[thefzsalam]

I just added an issue there: https://github.com/eclipse/eclipse.jdt.ls/issues/606

[YtvwlD]

This would be really helpful.