Switch from cdbs to dh; update packaging to latest standards

Debdiff for library package:

$ debdiff /var/cache/apt/archives/libxcb-render-util0_0.3.9-1+b2_amd64.deb libxcb-render-util0_0.3.10-1_amd64.deb
[The following lists of changes regard files as different if they have
different names, permissions or owners.]

Files in second .deb but not in first
-------------------------------------
-rw-r--r--  root/root   /usr/share/doc/libxcb-render-util0/README.md

Files in first .deb but not in second
-------------------------------------
-rw-r--r--  root/root   /usr/share/doc/libxcb-render-util0/README
-rw-r--r--  root/root   /usr/share/doc/libxcb-render-util0/changelog.Debian.amd64.gz

Control files: lines which differ (wdiff format)
------------------------------------------------
Homepage: [-http://xcb.freedesktop.org-] {+https://xcb.freedesktop.org+}
Priority: [-extra-] {+optional+}
Source: xcb-util-renderutil [-(0.3.9-1)-]
Version: [-0.3.9-1+b2-] {+0.3.10-1+}

Debdiff for devel package:

$ debdiff /var/cache/apt/archives/libxcb-render-util0-dev_0.3.9-1+b2_amd64.deb libxcb-render-util0-dev_0.3.10-1_amd64.deb
[The following lists of changes regard files as different if they have
different names, permissions or owners.]

Files in first .deb but not in second
-------------------------------------
-rw-r--r--  root/root   /usr/share/doc/libxcb-render-util0-dev/NEWS.gz
-rw-r--r--  root/root   /usr/share/doc/libxcb-render-util0-dev/README
-rw-r--r--  root/root   /usr/share/doc/libxcb-render-util0-dev/changelog.Debian.amd64.gz

Control files: lines which differ (wdiff format)
------------------------------------------------
Depends: libxcb-render-util0 (= [-0.3.9-1+b2),-] {+0.3.10-1),+} libxcb1-dev, libxcb-render0-dev
Description: utility libraries for X C Binding -- render-util {+(devel)+}
Homepage: [-http://xcb.freedesktop.org-] {+https://xcb.freedesktop.org+}
Installed-Size: [-48-] {+46+}
Priority: [-extra-] {+optional+}
Source: xcb-util-renderutil [-(0.3.9-1)-]
Version: [-0.3.9-1+b2-] {+0.3.10-1+}