Consolidate all environments in one section

Some of these names relate to specific tools, others could be used by multiple tools. In particular, virtualenv, the most popular tool for creating Python environments, does not mandate any of these and venv/ or .venv are simply conventional. It is more readable to group all of these together.

add *_plugin_import.cpp to Qt.gitignore

This file is autogenerated by qmake. It imports static plugin classes for
static plugins specified using QTPLUGIN and QT_PLUGIN_CLASS.<plugin> variables.

This file is autogenerated for static build

add .appx to VisualStudio.gitignore

ensure the following ! rules are included

Fixed typo

Add stackdump to Windows.gitignore

**Reasons for making this change:**

Ignore the stack dump generated when a program has crashed under Windows.

**Links to documentation supporting these rule changes:** 

http://www.drupalonwindows.com/en/blog/git-shell-windows-reports-shexe-has-stopped-working-appcrash
https://community.atlassian.com/t5/SourceTree-questions/Sourcetree-cannot-clone-pull-anymore-sh-exe-stackdump/qaq-p/82962

for .appx files created in the project root directory.

Ignore mypy's cache directory

Add moc_*.h in Qt.gitignore

Edit ignore for Microsoft Visio autosave files to include Office <= 2003

Added .tgz

Fixes issue excluding sub directories

Allow PakBlacklist-*.txt files inside Build dir in UnrealEngine.gitignore

Adding cmake-build-debug

Added .spyproject to ignored paths

[C] ignore versions of kernel module build results

Add pdfpc files to Tex.gitignore

Ignore mkdocs site directory

The presentation software pdfpc [1] (which is handy for latex beamer slides) supports additional notes on the secondary screen provided by *.pdfpc files.
These can be autogenerated from latex documents with the pdfpcnotes package [2], thus should be ignored in a latex project (but not in others where they could have been created manually).

[1] https://pdfpc.github.io/
[2] https://github.com/cebe/pdfpc-latex-notes

[mkdocs](http://www.mkdocs.org/) is rising as an alternative to Sphinx for project's documentation. The default build command puts the generated documentation in a `site` directory at the root of the project which should be ignored.

Fix macOS Icon

.project and .classpath should be inside VC

From the Eclipse Documentation: "Make sure that the .project and .classpath files are under version control. These files must be stored in the repository so that other users checking out the projects for the first time will get the correct type of project and will get the correct Java build path." - http://wiki.eclipse.org/FAQ_How_do_I_set_up_a_Java_project_to_share_in_a_repository%3F

Rails gitignore misuses double-asterisk

`**.` is invalid

Looks like Spyder 3.1 uses .spyproject folder to store workspace config