* One sc_context has only a single reader driver.
* remove dynamic reader driver loading capabilities
* remove opensc-tool -R command
* change the internal API, we don't need to pass around a "driver data" pointer as it can be found directly from the context.
* check in ./configure for only a single enabled reader driver
git-svn-id: https://www.opensc-project.org/svnp/opensc/trunk@4709 c6295689-39f2-0310-b995-f0e70906c6a9