Add filter preview images
Filter classes made for each new filter
Add methods to filters to get filter name and filter image
Removed filter application through AdCreationManager and changed it to be done in the filter activity

The enum thing for filters gets messy when there are lots of them, and
it is unnecessary now that we have a better filter system set up.
Adjusted default settings of filters to be in line with regular use.
Changed size of images in scroll view
Small fixes and comments added
Merge pull request #143 from elihart/moreFilters

More filters
Merge remote-tracking branch 'upstream/master' into improveMain