estream file paths incorrect if run in directory other than $VIM_CWD #6
Description
In most cases the estream $PWD is equal to the $VIM_CWD (this variable is provided by asyncrun). But if estream is run in a different directory, then the file paths returned to vim will be invalid.
estream should compare $PWD and $VIM_CWD, and properly handle the case where $PWD is a subdirectory of $VIM_CWD (or vice-versa, but only files within $VIM_CWD should be returned to the quickfix window). If estream is run outside of asyncrun, $VIM_CWD will not exist and estream should keep the current behavior.