Merge commit '23fd4689' as 'deps/c-timestamp'

deps/c-timestamp/.travis.yml

deps/c-timestamp/Makefile

deps/c-timestamp/README.md

deps/c-timestamp/t/compare.c

deps/c-timestamp/t/format.c

deps/c-timestamp/t/parse_malformed.c

deps/c-timestamp/t/parse_wellformed.c

deps/c-timestamp/t/tap.c

deps/c-timestamp/t/tap.h

deps/c-timestamp/t/tm.c

deps/c-timestamp/t/valid.c

deps/c-timestamp/timestamp.h

deps/c-timestamp/timestamp_compare.c

deps/c-timestamp/timestamp_format.c

deps/c-timestamp/timestamp_parse.c

deps/c-timestamp/timestamp_tm.c

deps/c-timestamp/timestamp_valid.c