Only <curl/curl.h> is needed typically and curl/types.h has been removed

Due to a design flaw, the CURLFORM_STREAM option doesn't really work
with curl_formget until after curl_easy_perform (or similar).

We don't author the bindings, they are created outside the main project.

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

As we now can specify all the socks proxy types with the regular --proxy
option using protocol prefix.

Using 'socks5h' as proxy protocol will make it a
CURLPROXY_SOCKS5_HOSTNAME proxy which is SOCKS5 and asking the proxy to
resolve host names. I found no "standard" protocol name for this.

Follow style of GNU layout (cp, mv ...) where options are separated with
comma: -o, --option

Order item alphabetically (by length also): -o, -O, --option

Follow style of GNU layout by moving help related options to the end:
--help, -M, --version

The internal defaults are important info

As it is a separate option it should have a .IP title

Clarify that the '-', '.', '_' or '~' letters are also not escaped since
they shouldn't according to RFC3986 section 2.3.

This is how this function has behaved since sep 2010, commit
5df13c31.

As the code already checks for it we can just as well make it official!

As it is already included by curlbuild.h if it exists on the platform it
was included here superfluously anyway.

Reported by: Dagobert Michelsen
Bug: http://curl.haxx.se/bug/view.cgi?id=3294509

Improved library search by check_function_exists_concat() macro:
it does not revert the list of libraries any more.

Improved OpenSSL library search: first find zlib, then search for
openssl libraries that may depend on zlib.

For Unix: openssl libraries can now be detected in nonstandard
locations. Supply CMAKE_LIBRARY_PATH to CMake on command line.

Added installation capability (very basic one yet).

When set to a HTTP 1.0 proxy, that only affects the CONNECT request and
not the regular HTTP request.

The new libcurl and command line options are now described.

Added CURLOPT_TRANSFER_ENCODING as the option to set to request Transfer
Encoding in HTTP requests (if built zlib enabled). I also renamed
CURLOPT_ENCODING to CURLOPT_ACCEPT_ENCODING (while keeping the old name
around) to reduce the confusion when we have to encoding options for
HTTP.

--tr-encoding is now the new command line option for curl to request
this, and thus I updated the test cases accordingly.

Clarified the release procedure

Error 4 has got a meaning

Error 48 has got a slightly different meaning now

When using -O the file will be saved in the current directory, and this
is now spelled out clearly.

Reported by: Hongli Lai