Changed the default fileroot to salve_root.

Instead of defaulting to the dir containing the root manifest, which
makes manifests behave inconsistently depending on the invoking manifest
tree, the fileroot is now SALVE root by default.
Also changed "file-root" commandline option to "fileroot".
Includes fixes for E2E tests.
Merge branch 'feature/salveroot-default-fileroot' into dev
Version bump to 1.1.0 and changelog additions.
Added a roadmap section to the readme.
Merge branch 'documentation/readme-1.1.0' into dev