adding input sanitizers for safety

regex match 500px instead of standard url explode since the full url of the photo can have the photo name in it after the id

0.2 final

- adding post time interval limitations
- changing options handler to be joined, since all the importers share it commonly at the moment

adding facebook

0.2 - adding flickr

left in the test post instead of the post collector

added date check
reformatted many comments

readme file is required

initial working alpha w/500px