Merge pull request #74 from cruessler/transliterate-default-key

make default_key transliterate non-ASCII characters
refine transliteration of default_keys
add 2 tests
Merge pull request #75 from cruessler/transliterate-default-key

refine transliteration of default_keys
make iconv a dev dependency

see #75
test for icon only once

see #75
install iconv gem only for ruby 2.0
make transliterate test more permissive

see #75
update changelog
working on 1.8 compatibility