Add fastlane in Android gitignore

Android keystore files are critical and losing them is destructive.

They should be commented out by default, the user should explicitly uncomment their line if they intend not to include them into their repository.

Please refer to [the official guide](https://intellij-support.jetbrains.com/hc/en-us/articles/206544839-How-to-manage-projects-under-Version-Control-Systems).
gradle.xml may contain user-specific local Gradle location.

Please refer to [the official guide](https://intellij-support.jetbrains.com/hc/en-us/articles/206544839-How-to-manage-projects-under-Version-Control-Systems).

and properly name the ART VM

Apart from requiring credentials to function correctly, keystores are sensitive data and are often stored inside the project's directory.

Add some files

This reverts commit f4cf36c5e1.

The `*/build` folder should be ignored because the android structure generate files and outputs inside this folder.

The captures folder is used by Android studio to keep heap dumps and other captures files. These are usually not shared as part of the source file.

build/ already matches all directories named 'build' in the repository,
regardless of level. Gradle can have more than two levels of project nesting.
However, /*/build/ matches only the 'build' directories of 2nd-level projects.
Thus, the first pattern is more appropriate than the second.

Gitignore the temp files directory generated by Android Studio's navigation editor tool.

Some files don't contain a line separator ('\n') at the end. Add the
missing eol.

In POSIX, all lines of text should end with a newline character by
definition. See
http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap03.html
section 3.397 for more.

See https://gist.github.com/jacknagel/1020172 for a gist of the issue.

The .project and important .classpath files are a part of an Android Eclipse
project, and their changes should be stored in the repository. Although there
may be a case for ignoring these files in very rare situations, they don't
justify belonging in a generic template.

The .project file is generally recreatable with a new import without
difficulty, but it still may have important configuration such as extra build
steps. More importantly, .classpath is absolutely essential for a project to
build correctly and cannot be automatically generated unless there is nothing
extra on the classpath.

Reverts commit 3ad9edaa2.

When exporting a signed .apk, Ecipse creates a proguard folder in the root directory. It should not be commited.