In order to support substituting a single file within
a larger package, and not substituting a directory wholesale,
this commit introduces the ability for SubstitutePath
to replace individual file paths if there is an exact match.
This behavior is backwards-compatible with the previous
configuration.
Fixes#3074
The repository is being switched from the personal account
github.com/derekparker/delve to the organization account
github.com/go-delve/delve. This patch updates imports and docs, while
preserving things which should not be changed such as my name in the
CHANGELOG and in TODO comments.
