supress chmod and touch warnings

On some file systems these commands will fail. It's unclear what systems
those are, I can reproduce it for touch() on my android phone (but not
on my tablet).

Instead of littering the output with potentially thousands of warnings
we supress them here. Ideally we should probably do something with them,
but I don't know what.

Maybe a strict setting that turns them into exceptions, would work? PRs
welcome.

extracted exceptions into their own files

required for PSR-2

check for broken iconv setup

use trusty for running tests on travis

Throw an exception when a file changes during reading

see discussion at splitbrain#17

added dogfooding test, extract self created archives

ignore null block headers

fixed size add in Fileinfo::frompath. closes splitbrain#9

adjusted tests

correctly remove temporary files when uncompressing ZIPs