Clean up and modernize Debian build

Let debhelper do all the hard work, basically.  Uses dh_autoreconf to
regenerate the configure script and so forth at build time.

Change-Id: Ice2ccd0d90d147fc4ed3b742531ffa4d0da7bbbc
Update changelog

Change-Id: Ie70ea4156325546df9d3abf738cacf15d26eb86a
.cvsignore -> .gitignore

Change-Id: I8e91f848ffad9af07b38502c7572e34f1dfd7520
Add build-depends on libx11-dev, libxtst-dev

Change-Id: I5a427e53cab445bd0ba0af0aa8a5546d4494f96a