Merge pull request #19 from pseyfert/master

enable history usage
Use preexec-hook instead of accept-line

When using accept-line, in some instances (for example in reverse
history search, see #19) the command-line would not be automatically
executet, because another widget might be used for executing.
Remove executable bit on config-file
Add history-support to defaultconfig
Add copyright-notice to all relevant files
Fix typo in abcd057f
Add changelog
Updated Arch Linux line in Readme.md
Bump version number