Add tex4ht to ubuntu-precise; resolves travis-ci/apt-package-whitelist#1143
Add tex4ht to ubuntu-precise; resolves travis-ci/apt-package-whitelist#1143

Packages: tex4ht tex4ht-common

travis-ci/apt-package-whitelist,christophgysin/apt-package-whitelist,christophgysin/apt-package-whitelist,AlCutter/apt-package-whitelist,travis-ci/apt-package-whitelist,AlCutter/apt-package-whitelist