More path manipulation functions in .sh/lib.

	- Added dump_path, append_path, prepend_path, fuzzy_ensure_path.
	- Rewrote ensure_path.
Most *ensure_path functions now take multiple paths.
Fix leftover debugging in fuzzy_ensure_path.
fuzzy_ensure_path now has -b flag to speciy binname.

Also fixed silly error calling ensure_path. Quoting $flags was causing
it to be treated as a path by ensure_path.
Import common java/android stuff into env.
Add empty .sh/env.d/Linux.
find_in_normpath now uses local for internal vars.
Use an in_path() for checking if something is in PATH.
use in_path() in .sh/xsession.