Support top-level patterns to external dirs using globstar

[TwitchBronBron]

Support using top-level patterns to external directories as long as there's at least 1 globstar. Example:

Consider this pattern:
"../thirdPartySDK/**/*"

For this path: ../thirdPartySDK/source/sdk.brs, its final path would be: ./source/sdk.brs because the globstar indicates the start of the relative path portion.

If there are multiple globstars, the first globstar is where the relative pattern will begin.