adding exception for *.spl from elsarticle.cls

Added *.opendb

[Fastlane] Specify screenshot files only, rather than whole folder (i…

[Fastlane] Specify screenshot files only, rather than whole folder (in case the user has frameit config)

The whole screenshots folder shouldn't be ignore since there could be frameit configuration in it (Framefile.json, fonts, background.jpg, *.strings, etc...). It'd be better to just ignore the generated PNG screenshot files.

Visual studio cache issue

/.vs/ do not catch the visual studio cache folder but .vs/ do

[Fastlane] Specify screenshot files only, rather than whole folder (in case the user has frameit config)

[TeX] Ignore generated *.xmpi files

Source: https://texdoc.net/pkg/xmpincl -> page 3:

> basically create a new file .xmpi

The whole screenshots folder shouldn't be ignore since there could be frameit configuration in it (Framefile.json, fonts, background.jpg, *.strings, etc...). It'd be better to just ignore the generated PNG screenshots.

Add shelf to JetBrains.gitignore

Added Apache NiFi .nar files

Added *.nlo and *.nls extensions to TeX.gitignore

Update Android.gitignore

Added MFractor's working folder to VisualStudio.gitignore

MFractor is a Xamarin/Visual Studio Mac productivity tool used by 1000's of Xamarin developers.

The `.mfractor/` folder should not be included in source control (but often is).

added: *.iobj, *.ipdb

Add a new .msix extension

Microsoft was announced a new extension of installer for Windows. I just added that one to be ignored as default, like others installers files.
References:
https://blogs.windows.com/buildingapps/2018/03/07/three-things-need-know-windows-developer-day/
https://github.com/Microsoft/msix-packaging

Fix the anchor to ignore section

Add the idea caches to gitignore

Ignore .idea/assetWizardSettings.xml for Android Studio 3.1

JetBrains: add .idea/httpRequests

This directory used by HTTP Client in IntelliJ IDEA (and other product).
https://www.jetbrains.com/help/idea/http-client-in-product-code-editor.html#viewingResponse

Add exclude credential master key of Rails 5.2

"These files are produced when Incremental Link-Time Code Generation (LTCG) is enabled."
https://stackoverflow.com/questions/31554559/possible-to-stop-generating-ipdb-iobj-files-by-visual-studio-2015

Improve JetBrains.gitignore styling