confirm the license statement about files i created
replace __gnu_cxx::stdio_filebuf with boost::iostreams
(re)unify client iostreams

boost::iostreams does not do lseek()s without being asked
extend try-block around entire function
use LDLIBS instead of LDFLAGS

LDLIBS are put behind the prerequisites by make's built-in rules so linking
won't fail with --as-needed.
release 0.3.1
Merge tag '0.3.1' into debian

0.3.1
New Build-Depends: libboost-iostreams-dev
Remove Build-Depends: pandoc-data

Depending on pandoc is sufficient again since 1.11.1-5.
release 0.3.1-1