backups/Makefile: upload: use bin/sync_upload

inputs/Makefile: download-logs: use bin/sync_upload like upload/download

bugfix: /README.TXT: `make inputs/upload`, `make inputs/download`: added live=1 so that the sync operation runs rather than previewing what will be synced. removed test=1 because this flag is not used by put.

bugfix: inputs/Makefile: upload, download: need to exclude files in .rsync_ignore, so that large local-only files, such as inputs/GBIF/raw_occurrence_record_plants/table*.tsv, do not have to be synced before `make inputs/upload` can complete (the corresponding .gz gets extracted instead); and deleted temp files in inputs/VegBIEN/TWiki/, such as active sessions, are not added back to the live copy on vegbiendev. previously, fixing this required extracting the rsync command run by `make inputs/upload`, etc. and manually editing it to exclude the applicable .rsync_ignore files, each time `make inputs/upload`, etc. was run (including before every column-based import).

bugfix: bin/make: need to leave bin/, ~/bin/ in the PATH when running make nonrecursively, so that commands invoked by it which are located in these dirs (e.g. put, which will be used by `make inputs/upload`) can still be found. this requires using command()'s new nonrecursive=1 flag instead of running no_PATH_recursion, so that no_PATH_recursion() only affects the resolution of the command path, but does not propagate the filtered PATH to the invoked command itself.

lib/sh/util.sh: command(): added nonrecursive=1 flag, which uses cmd2abs_path to run an external command nonrecursively

lib/sh/util.sh: added cmd2abs_path, which makes the command in $1 nonrecursive

bugfix: lib/sh/util.sh: PATH_rm(): also need to remove adjacent occurrences of the same path (or occurrences which become adjacent when other paths are removed), which :...: matching wasn't doing because the trailing : is consumed, preventing it from being matched at the beginning of the next path. since unlike filesystem paths with /, it is not necessary for a match to span multiple :-separated sections, we can just use new split() to split apart the PATH into an array of paths, filter each path, and join() them back together.

lib/sh/util.sh: added split()

lib/sh/util.sh: auto-echo common external commands: added `which`