First build of the pidgin++ package.

* Add some makedepends.

* Use a Bazaar branch targeted at building with makepkg.

* Use the winbuild.sh script instead of direct calls to make.

  The winbuild and pidgin-windev scripts have been updated to allow creating a
  minimal environment only with the dependencies that are missing in MSYS2 or
  that for some reason cannot work. For example, the GTK+ from MSYS2 is used
  instead of downloading one manually, but WinSparkle lacks a package in MSYS2
  and is thus downloaded.

* Some other small changes.
Add todo list for the pidgin++ package.
Improvements for the pidgin++ package.

* Remove make configuration since it has been implemented in Pidgin++.
* Some code refactoring.
More progress for the pidgin++ package.

* Disable the Sametime and SILC protocols.
  Pidgin++ has been updated to support this and also use the TCL library from
  MSYS2. Now the remaining binary downloads are pidgin-inst-deps and WinSparkle.

* Install EasyOptions.

* Add pidgin as a conflicting package.

* Fix missing checkout for the Bazaar branch.

* Update makedepends and other small changes.