export filePath to environment

[GheRivero]

exposing the file path to the environment makes easier to have a script to call flake8 with custom parameters

[steelbrain]

Instead of setting our current process's env, You should pass it like helpers.exec(filePath, [], {env: {FILE_PATH: "/path/to/file"}})

[Arcanemagus]

@GheRivero can you please address @steelbrain's comments? Since it's been a month if I get time I'll just implement this correctly and close this if I haven't heard back from you by then.

[Arcanemagus]

The scripts should now be running with the current directory set to that of the file, as such I'm going to close this PR.

@GheRivero if you have a use case that this doesn't fix please make your case why we should be polluting the runtime environment with extra variables 😛.