- Generate VQUIC and VSSH filenames in Visual Studio project files.

Prior to this change generated Visual Studio project configurations that
enabled SSH did not build properly. Broken since SSH files were moved to
lib/vssh 3 months ago in 5b2d703.

Fixes https://github.com/curl/curl/issues/4492
Fixes https://github.com/curl/curl/issues/4630
Closes https://github.com/curl/curl/pull/4607

Closes #854

After squashing most of our compiler warnings, up'ed the default
warning level from 3 to 4 in order to increase the likelyhood of
catching future warnings.

Updated the makefiles and Visual Studio project files to support moving
the authentication code to the new lib/vauth directory that was started
in commit 0d04e859e1.

find . -name .gitignore -print0 | xargs -i -0 sort -o '{}' '{}'

In addition to commit 709cf76f6b, removed the USE_SSLEAY preprocessor
variable from the Visual Studio project files as it isn't required
anymore.

Defined the DEBUGBUILD pre-processor variable to allow extra logging,
which is particularly useful in debug builds, as we use this and Visual
Studio typically uses _DEBUG.

We could define DEBUBBUILD, in curl_setup.h, when _MSC_VER and _DEBUG is
defined but that would also affect the makefile based builds which we
probably don't want to do.

As this pre-processor definition is defined in curl_setup.h there is no
need to include it in the Visual Studio project files.

Added support for WinIDN build configurations to the VC7 and VC7.1
project files.

A left over from the VC6 project files, so mainly cosmetic in Visual
Studio .NET as it can handle both comma and semi-colon characters for
separating multiple pre-processor definitions.

However, the IDE uses semi-colons if the value is edited, and as such,
this may cause problems in future for anyone updating the files or
merging patches.

Used the Visual Studio IDE to correct the separator character.