major overhaul

- organized code into several functions
- rewrote friendly bahaviour // more elegant checking for missing dates
- included timestamp functions wp_day() / wp_month() / wp_year() /
wp_yearmonth()
- changed name scheme for friendly csv to include country code
minor: updated version number
major: bug fixing of latest major

- solved several problems with empty vectors, data.frames and so on
minor: R CMD check succeeded
minor: checked if 'help' information is helpful
major: bug estermination

- the default date function as.Date and its helpers have unconvenient
behaviour especially when confronted with unregular strings -->
rewriting each and every as.Date method to fit my needs [s*** f******
f**** s***]
major: bug extermination

- rewriting wp_date as substitute for as.Date - finished
minor: Readme updates
minor: readme updates
minor: readme updates
minor: testing for cran release
minor: testing for cran release
minor: excluding readme_cache from git
Merge pull request #2 from petermeissner/going-for-version-0.2

version 0.2.0