which is ".target" directory.

As is clearly stated in the [eclipse documentation](http://wiki.eclipse.org/FAQ_How_do_I_set_up_a_Java_project_to_share_in_a_repository%3F).  
This gitignore has lead to much confusion in SO - please ammend

I would guess the same is true for .pydevproject and .cproject but can't
be sure/do not have any references on those

Also .launch configurations are generally meant to be versioned when
saved under project location. See for instance :
http://stackoverflow.com/a/337317/281545

This addresses #229

*** .externalToolBuilders/
This directory stores project-specific launch configurations for external tool builders, such as ant tasks that have to be executed to fulfill the build lifecycle

*** *.launch
It is possible to store "eclipse launch configurations" in external files. These (XML-)files may be stored anywhere within your projects and will be discovered by Eclipse automagically.

This is common amongst ruby projects in eclipse.