Fix broken example config

Fix #105
bugfix: properly expand env vars

If no sqlite path was specified, a new dir called $XDG_DATA_HOME was created
in the current dir. Also consistently use XDG_DATA_HOME.
print warning that events that cannot be parsed won't be available in khal

this fixes github issue #104
unified mode lines
contributors -> et. al/AUTHORS
removed old man page
better help message on failed `khal new`

this should close #102 on github
set local/default timezone as set on computer

this should fix #94 on github
new dependency: tzlocal>1.0
bugfix: default timezone setting was broken
fixed tests for default set timezones
updated CHANGELOG
doc: missing link inserted
doc: mention automatic timezone setting
doc: string types
doc: removed doc todos
tzlocal to requirements
doc: v0.3 released
v0.3 release
gitignore: added .cache
started to fix readonly issues