minor test file format fixes.
bugfix: when syslog was enabled in the "error_log" directive for nginx 1.7.1+, use of init_worker_by_lua or ngx.timer.at() would lead to segmentation faults. thanks shun.zhang for the report in #426.
tests: suppressed a warning from the test scaffold for a timer test case.
tests: fixed a test failure due to the misuse of the $TEST_NGINX_PORT variable.
tests: fixed a failure due to recent changes in the nginx core.
tests: use larger timeout limit for a test case revolved with external DNS resolving.
doc: various wording improvements and link fixes from Dayo Akanji.
doc: fixed some broken in-page links, as reported by smallfish in #421.
doc: typo fix from e路相扶.
bugfix: compilation error when PCRE is disabled in the nginx build. thanks Ivan Cekov for the report in #428.
suppressed a warning in the libc resolver.
tests: avoid using hard-coded DNS nameserver address but the TEST_NGINX_RESOLVER environment.
more fixes in the tests regarding the resolver.
updated valgrind.suppress to suppress a false positive on Amazon Linux i386.