setup-vms.h: sk_pop symbol tweak

Newer versions of curl are referencing a sk_pop symbol while the HP
OpenSSL library has the symbol in uppercase only.
url.c: fix parse_login_details() OOM handling
http_digest.c: SIGSEGV and OOM handling fixes
url.c: fix parse_url_login() OOM handling
build_vms.com: detect and use zlib shared image

Update the build_vms.com to detect and use zlib shared image installed
by the ZLIB kit produced by Jean-Francois Pieronne, and the also the
future ZLIB 1.2.8 kit in addition to the older ZLIB kits.

Also fix the indentation to match one of the common standards used for
VMS DCL command files and removed the hard tab characters.

Tested on OpenVMS 8.4 Alpha and IA64, and OpenVMS 7.3 VAX.
src/tool_paramhlp: try harder to catch negatives

strto* functions happily chomp off leading whitespace, so simply
checking for str[0] can lead to false negatives. Do the full parse and
check the out value instead.
curl.1: fix long line, found by checksrc.pl
src/tool: allow timeouts to accept decimal values

Implement wrappers around strtod to convert the user argument to a
double with sane error checking. Use this to allow --max-time and
--connect-timeout to accept decimal values instead of strictly integers.

The manpage is updated to make mention of this feature and,
additionally, forewarn that the actual timeout of the operation can
vary in its precision (particularly as the value increases in its
decimal precision).
sslgen.c: fix unreleased Curl_rand() infinite recursion
sslgen.c: fix Curl_rand() compiler warning

Use simple seeding method upon RANDOM_FILE seeding method failure.
slist.c, slist.h, cookie.c: new internal procedure Curl_slist_append_nodup()
Merge branch 'master' of github.com:bagder/curl

Merge for resync
ssluse.c,sslgen.c,sslgen.h: move certinfo support to generic SSL
x509asn1.c,x509asn1.h: new module to support ASN.1/X509 parsing & info extract
Use from qssl backend
config-os400.h: enable system strdup(), strcmpi(), etc.
OS400: add slist and certinfo EBCDIC support
OS400: new SSL backend GSKit
slist.c: fix indentation
curl_slist_append(): fix error detection
tests/Makefile.am: add configurehelp.pm to DISTCLEANFILES