install binary R packages with just one apt-get install call -- again

- otherwise the logs just look horrible: https://travis-ci.org/yihui/tikzDevice/builds/13447667, lines 365-700
- runtime penalty is substantial, too
Merge pull request #55 from krlmlr/sysinfo

before running test, print system information
Merge pull request #57 from krlmlr/selftest

add tests for installation of apt and GitHub packages
Make a few tweaks to `.travis.yml` tests.
Make a test quieter.
Merge pull request #59 from krlmlr/binary-install-single

install binary R packages with just one apt-get install call -- again
Tweak binary name generation.
Drop a section from the sample.

[ci skip]
add --latex option to bootstrap command to install TeXlive on Ubuntu

- use list of packages provided by Dirk
add test for --latex option in build matrix
install basic version of MacTeX package (BasicTeX)

- full version cannot be installed due to insufficient disk space (travis-ci/travis-ci#1586)
- use explicit Utah mirror recommended by MacTeX site, seems to be fastest
- remove package files after installation
process options in separate subroutine
remove debugging output for MacTeX install