Typecasts added since I changed more code to use long for timeouts

It was mostly typecasted to int all over the code so switching to long
instead all over should be a net gain.

cross-compilation of unit tests static library/programs fails when
libcurl shared library is also built. This might be due to a libtool or
automake issue. In this case we disable unit tests.

I removed the prefix as well accordingly.

Fix compiler warning: cast increases required alignment

Due to some flaw in roffit I removed some style changes to make the web
page look better.

Bug: http://curl.haxx.se/bug/view.cgi?id=3307835

Currently, Windows cross-compiled autobuilds require inclusion of setup.h
before curl.h to get definitions of CURL_STATICLIB and BUILDING_LIBCURL.

Source files given with relative paths do not have the
-D directory specifier prepended.

Fix compiler warning: conversion may lose significant bits

Fix compiler warning: variable was set but never used

Fix compiler warning: clobber ignored

Also define UNITTESTS macro when building unit test sources.

Fixing compiler warning: external definition with no prior declaration

When switching to HTTP because a HTTP proxy is being used, the existing
handler is now checked if it already is "compatible". This allows the https
handler remain while other non-http handlers will be redirected.

Bug: http://curl.haxx.se/mail/lib-2011-05/0214.html
Reported by: Jerome Robert

Fix compiler warning: variable was set but never used

Fix compiler warning: clobber ignored