build: return to standard use of 'autoconf'

Following http://sourceforge.net/p/opensc/mailman/message/32009859/

* 'configure.ac' is not mored created by bootstrap script, but present in source
* 'version.m4' is introduced and contains the 'volatile' package settings:
   settings that can be changed for the needs of particular build (ex. change PACKAGE_SUFFIX using the Git 'describe' or 'commit' data)
* 'bootstrap' script facilitate change of the package setting during the 'autoconf' phase