update ax_boost_base.m4

- from http://git.savannah.gnu.org/cgit/autoconf-archive.git/
- see https://github.com/bitcoin/bitcoin/issues/3219 and
- https://github.com/bitcoin/bitcoin/commit/efdfee423f23df88ffa4b846e4522419fb081ce1
update .gitignore
use ax_lib_curl.m4 from autoconf-archive
update autoconf files, incl libcurl version
add new m4 files, needed for AX_LIB_CURL
use AX_LIB_CURL from autoconf-archive
installCkon: add -v -Wall flags to autoreconf
installCkon: make prefix argument optional