Remove debian/ subdirectory

No need to have Debian specific files as the Debian maintainer will
supply the needed files.
Removed generated build files

config.guess and config.sub will be included by the build system.
Rename build files

bootstrap.sh is preferred over autogen.sh to avoid confusion with the
GNU Autogen package.

configure.in is obsolete and tools will require configure.ac and refuse
to process the file in the near future.
Remove RPM spec file

The RPM spec file will be maintained by downstream.
Add .gitignore

Ignore various generated files so Git will only care about files we care
about.
Update build system

Update to modern GNU Autotools and Gettext support.

Use and describe bootstrap.sh.

Add m4 macros to determine compiler warning flags.
Update sources to support Gtk+ 2.24

Also resolve various compiler warnings.
Updated translation files.

Due to source file changes, gettextize updated the po translation files
for source file line numbers.
Documentation updates

Update information on installation, to do list, changes, and new
maintainer.
Advance to 2.5~git for development