Fix .gitignore ignoring everything that wasn't yet tracked

[Crystalwarrior]

Currently, any additions to the repo will not be seen, even if it's in supposedly tracked folders - this is because the .gitignore wildcards are ignored due to its current set up. For example:

# Ignores everything
/*
# Except:
# the main plugin
!/addons/dialog_plugin/*

Will fail, because dialog_plugin is an ignored folder.
The solution is:

# Ignores everything
/*
# Except:
# the main plugin
!/addons/dialog_plugin/
!/addons/dialog_plugin/*

making the folder and the wild card both work. From what I understand, order matters. The folder has to be excepted FIRST, and the wild card added SECOND.
At the very least, the order matters if you want to make exceptions to exceptions - like I did by making it so .import files are not included regardless.

[Crystalwarrior]

Re-created from #27 to fix commit history shenanigans, I made a branch of a branch by accident there.

[AnidemDex]

Is a great idea, but it need some changes before being merged.