Treat relative paths wrt initial working directory
Treat relative paths wrt initial working directory

Summary:
Use resolve instead of filename_to_absolute, to resolve relative paths
in command line arguments with respect to the working directory infer
is initially invoked from, rather than the possibly-changed current
working directory of the child processes.

Also use initial instead of current working dir for default
project_root and results_dir

Reviewed By: martinoluca

Differential Revision: D3467571

fbshipit-source-id: fbb0f3f

kageiit/infer,ropas/infer,kageiit/infer,xennygrimmato/infer,xennygrimmato/infer,blzq/infer,blzq/infer,jvillard/infer,xennygrimmato/infer,facebook/infer,jsachs/infer,jsachs/infer,ryoon/infer,ropas/infer,blzq/infer,ropas/infer,jsachs/infer,ryoon/infer,xennygrimmato/infer,blzq/infer,facebook/infer,kageiit/infer,ropas/infer,kageiit/infer,facebook/infer,jvillard/infer,facebook/infer,jvillard/infer,blzq/infer,ryoon/infer,xennygrimmato/infer,ryoon/infer,jsachs/infer,jsachs/infer,kageiit/infer,xennygrimmato/infer,jvillard/infer,jvillard/infer,ryoon/infer,ryoon/infer,kageiit/infer,facebook/infer,facebook/infer,facebook/infer,xennygrimmato/infer,jsachs/infer,ropas/infer,blzq/infer,jvillard/infer,jvillard/infer,kageiit/infer,ropas/infer