Update troubleshooting instructions

[DenisGorbachev]

No description provided.

[hiroshi]

Thanks for your contribution.

However, disabling the open browser functionality may cause some troubles (see #109).

So we should add some notes for this section.

NOTE: Disabling the open browser functionality may cause some troubles (see https://github.com/gyazo/Gyazo-for-Linux/pull/109).

We'll add this line before/after merging this pull request.

[pastak]

@DenisGorbachev Would you tell us why you add this troubleshooting instructions.

I'm not agree to write it on README because this confuses user. I have no idea that this instruction works.

[hiroshi]

I can understand some people don't want to open images in a browser tab/window just after uploading.
Official Windows version of Gyazo client has this option in preferences for those.

Yep, but it should not be in the troubleshooting section of README I think. New sections like Tips or HowTo can be more suitable, or somewhere else I'm not sure.

[ghost]

I'm unable to find the .gyazo.config.yml file from $HOME/.gyazo.config.yml to add the:

browser_cmd: echo

code to prevent the web browser pop up. Any suggestions?